Download Physics, Grade 12, College Preparation Exam Review Package

SPH4C: Physics, Grade 12, College Preparation
Exam Review Package
Unit 1: Motion and Its Applications
Part A: Multiple Choice Questions
1.
A vector is different from a scalar because:
a.
b.
c.
d.
e.
a vector has a number and a unit whereas a scalar has a number only.
a vector has direction whereas a scalar does not have direction.
a vector has mass whereas a scalar does not have mass.
a vector measures speed whereas a scalar measures velocity.
a vector does not have a number whereas a scalar does have a number.
2.
Chen left home and went for a jog. He jogged 8.0 km [W], then 5.0 km [E] followed by 3.0 km [W].
What is Chen’s final position from home?
a. 0.0 km
b. 6.0 km [W]
c. 6.0 km [E]
d. 10.0 km [E]
e. 16 km [W]
3.
A runner makes 2 laps around a circular track, ending up at the same point she started from.
Which of the following pairs of quantities would both equal zero?
a. displacement and average velocity
b. average speed and average acceleration
c. distance and average speed
d. average speed and average velocity
e. displacement and average speed
4.
A car is travelling south while slowing down as it approaches a stop sign. The directions
associated with the object’s velocity and acceleration, respectively, are
a. [N], [S]
b. [N], [N]
c. [S], [S]
d. [S], [N]
e. not enough information to tell
5.
Which of the following statements about motion graphs is incorrect?
a. The slope of a position-time graph gives velocity.
b. The slope of a velocity-time graph gives acceleration.
c. The area under a velocity-time graph gives displacement.
d. The area under a position-time graph gives velocity.
e. The slope of an acceleration-time graph is zero when there is uniform velocity.
6.
A boy pulls on a wagon with a force of 100 N [E]. The wagon pulls on the boy with a force of
a. zero
b. less than 100 N [W] if the wagon’s speed is decreasing
c. 100 N [W] regardless of whether the wagon is accelerating
d. 100 N [W] only if the wagon is moving at constant velocity
e. greater than 100 N [W] if the wagon is accelerating
7.
If a car is travelling north at constant velocity, the net force acting on the car is:
a. directed north
b. directed south
c. zero
d. upward
e. downward
8.
The acceleration of an object is always in the direction:
a. of the initial velocity
b. of the average velocity
c. of the net force
d. of the force of friction
e. of displacement
9.
Which of the following statements is always true?
a. There are no forces acting on an object if it is at rest.
b. There is an unbalanced force on an object if it is in motion.
c. An object in motion has a tendency to stay in motion.
d. An object in motion has a tendency to come to rest.
e. An object in motion at constant velocity may or may not have an unbalanced force acting on it.
10.
If you were to increase the mass of an object in motion, the net force required to keep it moving at
the same rate of acceleration would:
a. increase
b. decrease
c. stay the same because the object was already in motion
d. be zero because the object is already in motion
e. either increase or decrease (too little information to tell)
Part B: Short Answer Questions
Please submit answers for this section electronically.
1.
(A)
Describe the motion depicted in the following position-time graph.
d [North]
t
The object is moving north with decreasing velocity.
(B) Given that the change in velocity is constant, sketch a velocity-time graph and an
acceleration-time graph to match the position-time graph above.
v-t graph
2.
a-t graph
A man is suing the bus company for a physical injury he received while riding on the bus. He
claims that the bus driver accelerated forward so quickly that a suitcase came flying from the
back of the bus hitting him in the head. Using Newton’s Laws, explain why this man does or does
not have a case.
According to Newton’s First Law, the suitcase, which was originally at rest,
would tend to stay at rest. Therefore it would tend to slide backward
toward the rear of the vehicle rather than forward. This man does not have
a case.
Part C: Problem Solving
1.
A motorcycle accelerates from rest to a velocity of 32 m/s [forward]. If its rate of acceleration was
2
7 m/s [forward], how long did it take him to reach this velocity?
Let forward be the positive direction.
a = v2 –v1 / Δt
Δt = v2 –v1 / a
Δt = (32 m/s – 0 m/s) / 7 m/s2
Δt = 4.571428 s
Δt = 5 s (accept 4.6 as well)
2.
In a period of 2.0 h, a sailboat travels 15 km [E] and then 11 km [W].
(a) What is the boat’s total distance travelled?
26 km
(b) What is the boat’s total displacement?
4 km [E]
(c) What is the boat’s final position?
4 km [E] of start
(d) What is the boat’s average speed (in km/h)?
v = 26 km / 2.0 h = 13 km/h
(e) What is the boat’s average velocity (in km/h)?
average velocity = 4 km [E] / 2.0 h = 2 km/h [E]
3.
Use the position-time graph below to answer the questions that follow.
(a)
Describe the motion of the object:
(i)
from 0.0 s to 15.0 s
Uniform velocity to the east
(ii)
from 15.0 s to 30.0 s
stationary
(iii)
from 30.0 to 40.0 s
Uniform velocity to the west
(b)
How do the motions of the object from 0.0s to 15.0 s and 30 s to 40 s
compare?
Opposite directions, velocity from 30 - 40 s is faster.
(c)
What is the velocity of the object at 10.0 s?
velocity = slope = 4 m [east] / 15 s = 0.3 m/s [east]
(d)
What is the acceleration of the object at 35.0 s?
zero
(e)
What is the position of the object at:
(i)
5.0 s
1.3 m [east]
(ii)
40.0 s
0.0 m
4.
Use the velocity-time graph below to answer the questions that follow.
(a)
Describe the motion of the object:
(i)
from 0.0 s to 20.0 s
Constant velocity of 2.0 m/s [east]
(ii)
from 35.0 s to 50.0 s
Constant velocity of 6.0 m/s [east]
(b)
How do the motions of the object from 20.0s to 35.0 s and 50.0 s to 60.0 s
compare?
20.0 s to 35.0 s – increasing velocity to the east
50.0 s to 60.0 s – decreasing velocity to the east (could say slowing
down or experiencing a westward acceleration as well)
(c)
What is the velocity of the object at 10.0 s?
2.0 m/s
(d)
What is the acceleration of the object at 30.0 s?
a = slope = 6.0 m/s - 2.0 m/s [east] / 35.0 s– 20.0 s = 0.26666 = 0.27
m/s2 [east]
(e)
What is the displacement of the object after the first 20.0 s?
Displacement = area = (20.0 s) (2.0 m/s [east]) = 40.0 m [east]
5.
A block is being pushed forward on a flat surface with a force of magnitude 45 N. The force of
friction on the block is 13 N. The mass of the block is 11 kg.
(a)
Draw a free-body diagram of the block.
FN
Ff
Fapp
Fg
(b)
What is the net force acting on the block?
Fnet = 45 N [forward] + 13 N [backward] = 32 N [forward]
(c)
What is the acceleration of the block?
Fnet = ma
a = Fnet / m
a = 32 N [forward] / 11 kg
a = 2.9 m/s2 [forward]
Unit 2: Mechanical Systems
Part A: Multiple Choice Questions
Select the correct response for each question.
1.
The term “weight” in physics means the same thing as
A)
B)
C)
D)
2.
A box with a mass of 9.5 kg is sitting on the floor. The magnitude of the normal force acting on
the mass:
A)
B)
C)
D)
3.
mass
applied force
force of gravity
tension force
is 9.5 N
is 93 N
cannot be found with the information given
0.97 N
What type of lever is a wheelbarrow?
A)
B)
C)
D)
4.
The turning effect on a rigid bar around a pivot point is referred to as
A)
B)
C)
D)
5.
5
0.4
2.5
2
In a pair of gears, the gear where the effort is applied has 4 teeth and the gear with the load
attached has 12 teeth. The:
A)
B)
C)
D)
10.
320 N∙m
32 000 N∙m
1600 N∙m
80 000 N∙m
The ideal mechanical advantage of a ramp with a height of 2.0 m and length of 5.0 m is:
A)
B)
C)
D)
9.
3
4
5
100%
A person lifts a wheelbarrow from the handles located 125 cm from the wheel which acts as the
fulcrum. The person lifts with a force of 640 N, and the load is located 50 cm from the wheel. The
effort torque is equal to
A)
B)
C)
D)
8.
9.8 N
49 N
1.96 N
0.2 N
A moveable pulley system has four support strings. What is the ideal mechanical advantage of
this system?
A)
B)
C)
D)
7.
applied force
tension
torque
frictional force
A student is moving dirt with a shovel. He must lift 1.0 kg of dirt into a bucket and the load arm is
1.50 m away from the pivot end of the shovel and the effort arm is 0.30 m (this is a third-class
2
lever with g = 9.8 m/s ). The load force is:
A)
B)
C)
D)
6.
first-class
a wheelbarrow is not a lever
second-class
third-class
IMA is 3
IMA is 0.3
AMA is 3
AMA is 0.3
If the amount of friction present in a moving machine increases,
A)
B)
C)
D)
11.
the AMA decreases and the percent efficiency decreases
the AMA increases and the percent efficiency increases
the AMA increases and the percent efficiency decreases
the AMA decreases and the percent efficiency increases
The torque is greatest on an object when
A)
B)
C)
D)
the effort force is applied parallel to the object and as close to the fulcrum as possible
the effort force is applied perpendicular to the object and as close to the fulcrum as
possible
the effort force is applied perpendicular to the object and as far from the fulcrum
as possible
the effort force is applied parallel to the object and as far from the fulcrum as possible
Part B: Short Answer Questions
1. Friction can be your best friend or your worst enemy. Describe a situation where friction is helpful
in your daily life and a situation where friction is not helpful.
Friction is helpful when you are driving a car. Without enough friction, the
wheels would not grip the road (as in icy conditions).
Friction is not helpful when downhill skiing. Skiers like to wax their skis to
reduce the amount of friction between their skis and the snow.
2.
Identify the class of lever of these common household items. Choose from the list on the right.
__1__ second-class lever
__4_ second-class lever
__5_ third-class lever
__2_ first-class lever
__3_ first class lever
1.
2.
3.
4.
5.
nut cracker
pliers
scissors
bicycle crank
barbecue tongs
Part C: Problem Solving
1.
A 10 kg cardboard box is pushed across the floor with a horizontal force of 50 N [right]. If µk =
2
0.080, then what is the acceleration of the box? (remember, g = 9.8 m/s ).
Given:
Letting forward be the positive direction,
m = 10 kg
Fapp = 50 N
µk = 0.080
Required:
a
Analysis and Solution:
FNET = ma
Since FNET = Fapp + (-Ff),
Fapp + (-Ff) = ma
50 N – Ff = (10 kg) a
Since Ff = µk FN and FN =Fg = mg,
50 N - µk m g = (10 kg) a
50 N – (0.080) (10 kg) (9.8 m/s2) = (10 kg) a
50 N – 7.84 N = (10 kg) a
4.216 m/s2 = a
Paraphrase: The acceleration would be 4.2 m/s2.
2.
A 2.0 m long bar is being used as a first-class lever. It has a load of 720 N placed on one end
(located 1.2 m from the fulcrum) and the effort is being applied at the opposite end.
(a)
State the Law of the Lever.
The Law of the Lever states that the magnitude of the effort torque
must be equal to the magnitude of the load torque, but in opposite
directions.
(b)
Draw a diagram of the lever, showing the load, effort, fulcrum, effort arm,
and load.
(c)
Determine the effort force needed to balance the load.
FEdE = FLdL
FE = FLdL / dE
FE = (720 N) (1.2 m) / (1.8 m)
FE = 480 N
(d)
If this lever has an actual mechanical advantage of 1, determine the
percent efficiency of the lever.
IMA = dE / dL
IMA = 1.8 m / 1.2 m
IMA = 1.5
% efficiency = (AMA / IMA) × 100 = (1 / 1.5) × 100 = 67 %
Unit 3: Energy Transformations
Part A: Multiple Choice Questions (10 marks)
Select the correct response for each question.
1.
A ball is thrown up into the air. As it rises:
(a)
its gravitational potential energy increases and its kinetic energy increases
(b)
its gravitational potential energy increases and its kinetic energy decreases
(c)
its gravitational potential energy decreases and its kinetic energy decreases
(d)
its gravitational potential energy decreases and its kinetic energy decreases
2.
If a 1000 kg car accelerates from 10 m/s to 20 m/s, the amount of work done is:
(a)
112 500 J
(b)
10 000 J
(c)
150 000 J
(d)
5000 J
3.
If mechanical energy is conserved, then
(a)
the sum of the kinetic energy and gravitational potential energy remains constant
(b)
the amount of kinetic energy is constant
(c)
thermal energy losses due to friction are constant
(d)
the amount of gravitational potential energy is constant
4.
The amount of energy required to raise a 20 kg child onto a countertop that is 1.25 m off the
2
ground is (g=9.8 m/s )
(a)
30 J
(b)
0.25 N
(c)
245 J
(d)
30 N
5.
A cyclist has 4 100 J of energy. The velocity of this 82 kg cyclist (with bike) is
(a)
100 km/h
(b)
50 km /h
(c)
100 m/s
(d)
10 m/s
6.
The amount of energy used by a 60 W light bulb in 1 hour is
(a)
216 000 J
(b)
1J
(c)
60 J
(d)
60 W
7.
An electrical device outputs 40 J of radiant light energy for every 100 J of electrical energy input.
The efficiency of this device is
(a)
0.4
(b)
40 %
(c)
0.6
(d)
60 %
8.
Which of the following energy transformations best describes the operation of a solar powered
battery charger?
(a)
(b)
electrical energy --> thermal energy --> kinetic energy
nuclear energy --> potential energy --> chemical energy
(c)
(d)
thermal energy --> elastic potential energy --> electrical energy
radiant energy --> electrical energy --> chemical potential energy
o
9.
A cup of water is boiling at 100 C.
(a)
its thermal energy is 100 J
o
(b)
the average kinetic energy of the particles is greater than in a 90 C cup of water
(c)
the particles of water are not moving
(d)
the particles of water are moving at 100 m/s
10.
If a frictional force of 15 N acts on a box as it slides a distance of 5 m, the thermal energy
produced would be:
(a)
3J
(b)
37.5 J
(c)
6J
(d)
75 J
Part B: Short Answer Questions
1.
2.
Match each word with the most appropriate choice by filling in the correct number. (6 marks)
__4_ power
__5_ energy
__1_ watt
1.
2.
3.
__6_ elastic
__3_thermal
__2_radiant
4.
5.
6.
metric unit of power
light energy from electromagnetic waves
total energy due to movement of particles within a
substance
rate at which work is done
the ability to do work
type of energy stored when a spring is stretched
Explain the difference between renewable and non-renewable energy resources. Give one
example of each. State one advantage and disadvantage of each example you give. (5 marks)
A non-renewable resource is a resource that cannot be regenerated
within an average human lifespan; whereas, a renewable resource can
be regenerated within an average human lifespan.
Non-renewable – burning of fossil fuels, advantage – fairly inexpensive
method of providing energy, disadvantage – pollution
Renewable – wind energy, advantage – low pollution, disadvantage –
fairly expensive – many windmills required to produce substantial
energy which requires space (noise / appearance not readily accepted)
3.
Explain how a $10.00 compact fluorescent light bulb (15 W) can cost less than an incandescent
light bulb (60 W) that costs $0.50. (2 marks)
A compact fluorescent light bulb is more efficient than an incandescent
light bulb. 90 – 95% of the energy supplied to an incandescent bulb is lost
as thermal energy, whereas only about 40 % is lost in a CFL. Therefore, it
costs less to operate a CFL than it does to operate an incandescent bulb.
Furthermore, incandescent bulbs must be replaced more often.
4.
Explain how you could determine the efficiency with which the mechanical energy of a pendulum
is conserved. (4 marks)
Raise the pendulum to a specific height. Measure the initial height of the
pendulum with respect to its lowest possible point (e.g., position at rest).
Use the equation for gravitational potential energy to determine the total
mechanical energy initially present when the pendulum is at this initial,
highest point. Release the pendulum and note the height to which the
pendulum reaches on the other side. Use this final height to determine the
energy output (e.g., the final energy). Then divide the final energy (Eout) by
the initial energy (Ein). The resulting ratio gives the efficiency.
Part C: Problem Solving
1.
a)
An apple (0.100 kg) is thrown vertically upward at a speed of x m/s (from an arm 1.5 m
2
off of the ground). What is the maximum height that the apple reaches? (g=9.8 m/s )
b) With what speed will the apple return to the thrower if mechanical energy continues to be
conserved? Why?
2.
A 0.25 kg pendulum swings through its minimum height of 0.50 m from the ground with a
2
maximum speed of 3.1 m/s. How fast is it moving when it is x m off of the ground? (g= 9.8 m/s )
3.
How much light energy is radiated from a 10% efficient light bulb if electrical energy is supplied at
the rate of 60 W for a time period of x. (Remember, there are 3600 s in 1 h)
Unit 4: Electricity and Magnetism
Part A: Multiple Choice Questions (11 marks)
Select the correct response for each question. You may change your answer after making your initial
selection, but remember that your first instinct is often your best one!
1.
If two 100 Ω resistors are placed in series, their total resistance is:
(a)
100 Ω
(b)
200 Ω
(c)
10 000 Ω
(d)
50 Ω
2.
The potential difference across a 100 ohm resistor that has 0.01 amperes of current is:
(a)
0.01 volts
(b)
100 volts
(c)
1 volt
(d)
10 000 volts
3.
A load that has 2 A of current passing through it with a potential difference of 6 V has a resistance
of:
(a)
2Ω
(b)
2/6 Ω
(c)
12 Ω
(d)
3Ω
4.
If two 200 Ω resistors are connected in parallel, their total resistance is:
(a)
100 Ω
(b)
200 Ω
(c)
400 Ω
(d)
50 Ω
5.
If five light bulbs are connected in series to an energy source and one of them burns out, the
others:
(a)
go out
(b)
become brighter
(c)
become dimmer
(d)
are not affected
6.
How do potential drop and potential rise compare in a completed simple circuit?
(a)
Potential rise does not affect potential drop.
(b)
Potential rise in the source is equal to the potential drop in the load.
(c)
Potential rise in the source is greater than potential drop across the load.
(d)
Potential rise in the source is less than potential drop across the load.
7.
How will the current in the first ammeter compare with the reading in the second?
(a)
A1 has a current reading while
A2
has a reading of zero.
(b)
A1 and A2 are equal.
(c)
A1 is less than A2.
(d)
A1 is greater than A2.
8.
Which of the following graphs best represents the relationship between electric potential
difference and current for an ohmic resistor?
(a)
(b)
(c)
(d)
9.
The direction of current flow is shown in the conductor below. What would be the direction of the
magnetic field lines around the conductor on the side of the conductor closest to you?
(a)
(b)
(c)
(d)
upward
downward
to the right
to the left
10.
In the diagram below,
(a)
the magnetic field lines between the poles are directed from left to right, the current is
flowing away from you into the page, and the wire is forced upward toward the middle of
the magnet.
(b)
the magnetic field lines between the poles are directed from right to left, the
current is flowing away from you into the page, and the wire is forced upward
toward the middle of the magnet.
(c)
the magnetic field lines between the poles are directed from right to left, the current is
flowing toward you, and the wire is forced downward away from the magnet.
(d)
the magnetic field lines between the poles are directed from right to left, the current is
flowing toward you, and the wire is forced to move downward away from the magnet.
11.
In the following electromagnet,
(a)
the current in the wires on the side closest to you is directed upwards and the north pole
is on the left.
(b)
the current in the wires on the side closest to you is directed downwards and the north
pole is on the left.
(c)
the current in the wires on the side closest to you is directed upwards and the north pole
is on the right.
(d)
the current in the wires on the side closest to you is directed downwards and the
north pole is on the right.
Part B: Short Answer Questions
Please submit answers for this section electronically.
1.
Match each word with the most appropriate choice by filling in the correct number. (9 marks)
__8_ current
_4__ volt
__6_ load
_7__ampere
__9_ short
_5__
conductor
__2_ DC
__3_ AC
___1_ open
2.
1.the type of circuit that contains an electrical gap so that no current can
flow
2. flow of current in one constant direction
3. the flow of current occurs back and forth with a regular frequency
4. the metric unit for electric potential difference
5. a medium that allows current to flow
6. a device that transforms electrical energy into other forms of energy
7. the metric unit of electrical current
8. the flow of electric charge
9. the type of circuit that contains a continuous path with no load
Explain the best type of connection for the following parts within an electrical circuit: series or
parallel. Provide reasons for your answers. (4 marks)
(a) lights in your house
- are not connected in series. In a parallel circuit you can turn one
on without turning on all of them; this means each must have its own
individual pathway. Also, provides brighter light (no sequential voltage
drop across each successive light).
(b) 1.5 V batteries to power a 6.0 V electronic device
-
3.
(a)
must be connected in series. 4 of these 1.5 V batteries would
have to be connected in series so that their individual potential
gains can add together providing enough energy to power the 6.0
V device.
Label the parts of the DC motor. (5 marks)
1. conductor
2. external
magnet
3. split-ring
commutator
4. carbon brushes
5. armature
(b)
Explain the Motor Principle in relation to the operation of the DC
motor. (2 marks)
The motor Principle states that a current-carrying conductor placed
in an external magnetic field will experience a force that is
perpendicular to the direction of the current and to the direction of
the external magnetic field lines. In a DC motor, current flows
through the wire helping make up the armature. Because this
armature is placed in an external magnetic field, it experiences a
force and, as a result, rotates.
(c)
Explain the role of the commutator in the DC motor. (2 marks)
The role of the commutator is to allow current though the wire on the
armature to switch directions every half-rotation. When this
happens, the magnetic field around the armature also changes
direction. This allows the armature to keep spinning in one constant
direction.
Part C: Problem Solving
For this section, you must print the test to fully complete all questions showing complete solutions
with proper communication. You must also submit final answers electronically as you complete
the test.
1.
Use the circuit below to answer the following questions. (7 marks)
(a) What is the potential difference across R1?
(b) If 10 A flows out of the battery, what is the current through R1?
(c) What is the resistance of R1?
(d) What is the resistance of the 7 V load?
(a) Vt = V1 + V2 (KVL)
20 V = V1 + 7 V
20 V – 7 V = V1
13 V = V1
(b) It = I1 (KCL). Therefore, I1 = 10 A.
(c) R = V / I (Ohm’s Law)
R1 = 13 V / 10 A
R1 = 1.3 Ω
(d) R2 = V / I = 7 V / 10 A = 0.7 Ω
2.
Use the circuit below to answer the following questions. (9 marks)
(a) Vt = V1 = 20 V (KVL)
(b) Vt = V2 + V3 (KVL)
20 V = V2 + 6 V
20 V – 6 V = V2
14 V = V2
(c) R1 = V1 / I1
R1 = 20 V / 20 A
R1 = 1 Ω
(d) R2 = V2 / I2
R2 = 14 V / 10 A
R2 = 1.4 Ω
(e) It = I1 + I2
It = 20 A + 10 A
It = 30 A
Unit 5: Hydraulic and Pneumatic Systems
Part A: Multiple Choice Questions
1.
Which of the following is an acceptable unit for density?
(a)
g / mL
(b)
mL / g
3
(c)
L/m
(d)
g / kg
2.
When area doubles for a constant applied force, the pressure:
(a)
doubles
(b)
halves
(c)
becomes 4 × the original pressure
(d)
becomes ¼ the original pressure
2
3.
The force applied to an object that experiences 30 kPa of pressure over 0.02 m is:
(a)
600 N
(b)
0.6 N
(c)
1500 N
(d)
0.0007 N
4.
A 2-cylinder system is constructed so that the output force is 10 times the input force. How does
the input cylinder area compare to the output cylinder area?
th
(a)
The input cylinder’s area is 1/10 the area of the output cylinder.
(b)
The input cylinder’s area is 10 times the area of the output cylinder.
th
(c)
The input cylinder’s area is 1/100 the area of the output cylinder.
(d)
The input cylinder’s area is 100 times the area of the output cylinder.
5.
When the cross-sectional area of a fluid-carrying pipe decreases, the flow speed of the fluid will:
(a)
increase
(b)
decrease
(c)
stay the same
(d)
change unpredictably
6.
The state of matter that has the least force of attraction between its particles is:
(a)
solid
(b)
liquid
(c)
gas
(d)
Neither. They all have the same force of attraction between their particles.
7.
Which of the following substances would likely have the best laminar flow?
(a)
water
(b)
cool honey
(c)
warm honey
(d)
vegetable oil
8.
In terms of the air flow around an airplane wing, it is true that underneath the wing:
(a)
Air flows more slowly and there is lower pressure than above the wing.
(b)
Air flows more quickly and there is lower pressure than above the wing.
(c)
Air flows more slowly and there is higher pressure than above the wing.
(d)
Air flows more quickly and there is higher pressure than above the wing.
9.
The correct order of the following substances from least to maximum compressibility is:
(a)
wood , oil, oxygen
(b)
oil, wood, oxygen
(c)
oxygen, wood, oil
(d)
oxygen, oil, wood
10.
If the gauge pressure is 150 kPa and the atmospheric pressure is 100 kPa, the absolute pressure
is:
(a)
250 kPa
(b)
50 kPa
(c)
150 kPa
(d)
100 kPa
Part B: Short Answer Questions
1.
Match each word with the most appropriate description by putting the correct number in the blank.
(6 marks)
__1___. Pascal
__7___. Volume
___6__. Hydraulic
__2___. Drag
4. experiences attractive forces while
constantly in motion
___8__. fluid dynamics
5. the process of minimizing resistance to
motion
6. a system that works using liquid under
pressure
7. the amount of space a substance takes up
8. the study of the motion of fluids and the
factors that affect that motion
___5__. Streamlining
__4___. Particle
__1___. density
2.
1. a measure of how closely particles are
packed together.
2. a force that resists the motion of an object
through a fluid
3. a force of 1 newton per square metre
Explain the meaning of fluid viscosity and its relation to laminar flow. (2 marks)
Fluid viscosity is a measure of the internal friction of a liquid. The more
internal friction in a liquid, the more viscous it is, and the more it resists
flow. Because of its internal friction, the layers of liquid are less likely to
slide in front of neighbouring layers causing mixing and disturbance.
Because of this decreased occurrence of turbulence, there is more laminar
flow.
3.
State Bernoulli’s Principle. Describe how it contributes to the design of an airplane’s wing. (3
marks)
Bernoulli’s Principle states that in regions where the flow of fluid is fast,
there is low pressure and in regions where fluid flow is slow, there is
higher pressure.
As airplane wing is curved on the top and flatter on the bottom. Because of
this, the air that the airplane is travelling through has to move faster over
the top of the wing (longer distance due to the curve) than it does under the
wing (shorter distance to travel) so that the same air reunites after the
airplane has travelled through. Applying Bernoulli’s Principle, the faster
moving air above the wing contributes to lower pressure in this location
than in the area below the wing where fluids are moving more slowly. With
high pressure below the wing, and low pressure above the wing, the plane
experiences an upward lift.
Part C: Problem Solving
1.
Explain (with calculations) why a person with a weight of 500 N gets punctured when resting on a
single nail, but remains unharmed when lying on a bed of nails. Let the area of one nail be 0.00
2
005 m and use a bed of about x nails. (3 marks)
Sample Solution:
In terms of pressure:
On one nail:
P = F / A = 500 N / 0. 00 005 m2 = 10 000 000 Pa = 10 000 kPa
On a bed of nails:
A = 0.00 005 m2 × 2000 = 0.1 m2
P = F / A = 500 N / 0.1m2 = 5000 Pa = 5 kPa
Therefore, when the force is spread out over many nails, there is less
pressure at the location of each nail and the skin will not be punctured.
SPH4C: Physics, Grade 12, College Preparation – Full/Mixed Review
PART A:
Short Answer Questions
a.
1.
State Newton’s Three Laws of motion. For each law, describe a situation that demonstrates
the law. [6]
Newton’s First Law: An object in motion will tend to stay in motion unless acted
upon by an external force. E.g., if a car comes to a sudden stop, passengers tend
to stay in motion unless external forces, such as friction and a seatbelt’s applied
force, stop them.
Newton’s Second Law: An object’s acceleration is proportional to the net
force acting on it and inversely proportional to its mass. E.g., if you apply more
force to a wagon you are pulling, it will accelerate in the direction of that pull.
However, if you are pulling it with constant force when additional mass is added,
the rate of acceleration will decrease.
Newton’s Third Law: For every action force there is an equal and opposite
reaction force. E.g., if you push on wall with a force of 50 N, the wall pushes back
on you with a force of 50 N.
2.
Describe an example to explain the difference between the definition of work used by physicists
and that of the average “person on the street”. [2]
In physics, work is done when a force is applied to displace an object. In
everyday language, a person holding a weight outstretched in front of their
body, or studying for a physics exam would be doing a lot of work, but
according to the physics definition, s/he would not be.
3.
Describe the motion shown in the following graph. Include at least two pieces of information and
the reason for your conclusions. [2]
Object is moving north (positive
slope)
Velocity is increasing (slope is
increasing)
4.
When applying force on a lever, what two things can you do to maximize torque? [2]
apply the force as far from the fulcrum as possible
apply the force perpendicular to the lever
5.
(a) Give the energy transformation equation for one complete ball bounce. [2]
GPE → KE → elastic PE + thermal energy + sound energy → KE→GPE
(b) Explain how you could determine the efficiency with which the mechanical
bounce is conserved. [3]
energy of a ball
Raise the ball to a specific height. Measure the initial height of the ball with
respect to the floor. Use the equation for gravitational potential energy to
determine the total mechanical energy initially present when the ball is at this
initial, highest point. Release the ball and note the height to which the ball
reaches after the bounce. Use this final height to determine the energy output
(i.e., the final energy). Then divide the final energy (Eout) by the initial energy
(Ein). The resulting ratio gives the efficiency.
6. (a)
Show the location of the north and south poles for this electromagnet. [1]
Answer: north on the right, south on the left
(b) Show the direction of force on this current-carrying conductor. [1]
Answer: up the page, into centre of magnet
7.
(a)
Label the parts of the DC motor. [5]
1. _conductor___
2. external
magnet
3. split-ring
commutator
4. carbon
brushes__
5. _armature__
(b)
Explain the operation of the DC motor. Also, which way, clockwise or counter-clockwise,
will the above motor rotate? [2]
The Motor Principle states that a current-carrying conductor placed
in an external magnetic field will experience a force that is
perpendicular to the direction of the current and to the direction of
the external magnetic field lines. In a DC motor, current flows
through the wire helping make up the armature. Because this
armature is placed in an external magnetic field, it experiences a
force and, as a result, rotates clockwise (the armature has a N pole
on the left (upper) end).
PART B:
Problems
1.
A receiver on a football team runs 8.0 m [E] and then turns abruptly to run 12.0 m [W]. If the
entire motion takes 5.0 s, determine the receiver’s
(a)
total distance travelled. [2]
(b)
total displacement. [2]
(b)
average speed. [2]
(c)
average velocity. [2]
(a) Δd = 8.0 m + 12.0 m = 20 m
(b) displacement = 8.0 m [E] + 12 m [W] = 4.0 m [W]
(c) v = Δd / Δt = 20 m / 5.0 s = 4.0 m/s
(d) velocity = displacement / time = 4.0 m [W] / 5.0 s = 0.80 m/s [W]
2.
Ms. Fizics pushed a large crate of textbooks (75 kg) down the hall to her office. She pushed as
2
hard as she could and the crate accelerated down the hall at a rate of 1.5 m/s . There was a
coefficient of kinetic friction of 0.48 between the crate and the floor.
(a)
Draw a free-body diagram for the crate. [2]
(b)
Determine the net force on the crate. [2]
(c)
Determine the crate’s normal force. [2]
(d)
Determine the force of friction on the crate. [2]
(e)
Determine the force exerted by Ms. Fizics. [2]
(a)
3.
(b)
Fnet = ma
Fnet = (75 kg) (1.5 m/s2)
Fnet = 112.5 N = 110 N [forward]
(c)
FN = Fg = mg = (75 kg)(9.8 N/kg) = 735 N = 740 N [up]
(d)
Ff = µ FN = (0.48) (735 N) = 353 N = 350 N [backward]
(e)
Fnet = Fapp + Ff
Fapp = Fnet - Ff
Fapp = 112.5 N [forward] - 353 N [backward]
Fapp = 112.5 N [forward] + 353 N [forward]
Fapp = 465.5 N [forward] = 470 N [forward]
A 2.0 m first-class lever has a load of 600 N located 0.5 m from the fulcrum.
(a)
State the Law of the Lever. [1]
The Law of the Lever states that the magnitude of the effort torque
must be equal to the magnitude of the load torque, but in opposite
directions.
(b)
Draw a diagram of the lever, showing the load, effort, fulcrum, effort
arm, and load. [2]
(c)
Determine the effort force needed to balance the load. [2]
FEdE = FLdL
FE = FLdL / dE
FE = (600 N) (0.5 m) / (1.5 m)
FE = 200 N
(d)
If this lever has an actual mechanical advantage of 2, determine the
percent efficiency of the lever. [2]
IMA = dE / dL
IMA = 1.5 m / 0.5 m
IMA = 3.0
% efficiency = (AMA / IMA) × 100 = (2 / 3) × 100 = 67 %
b.
4.
A 60 kg snowboarder (including equipment) heads down a very slippery slope starting at
a height of 100 m, from rest, above the flat surface at the bottom. Use the Law of Conservation
of Energy to determine the speed she could attain by the time she hits the flat (at the bottom of
the hill). [4]
ET top = ET bottom
Eg top = Ek bottom
mgh = ½ mv2
gh = ½ v2
v = √2gh
v = √(2)(9.8 m/s2)(100 m)
v = 44 m/s
5.
Use the circuit diagram below to answer the questions that follow.
a)
What is the resistance of R1 ? [2]
R1 = V1 / I1
R1 = 20 V / 10 A
R1 = 2 Ω
(b)
What is the current through R2 ? [2]
I2 = V2 / R2
I2 = 20 V / 4 Ω
I2 = 5 A
(c)
What is the current through the energy source? [2]
IT = 10 A + 5 A = 15 A
(d)
What is the total resistance in the circuit? [2]
1 / RT = 1/ R1 + 1/ R2
1 / RT = 1 / (2 Ω) + 1 / (4 Ω)
1 / RT = (2 + 1) / 4Ω
RT = 4 Ω / 3
RT = 1.3 Ω
PART C:
Multiple Choice Questions
1. A net force acts on an object. The object will likely:
a.
b.
c.
d.
e.
move at constant speed
remain stationary
accelerate
come to a stop and remain stationary
move at constant velocity
2. In Newton’s Third Law, the action and reaction forces:
a.
b.
c.
d.
e.
are only equal if the object is moving with constant velocity
are only equal if the object is experiencing a net force
are only equal if the object is stationary
act on the same object
act on different objects
3. A vector is different from a scalar because:
c.
d.
e.
f.
g.
A vector has a number and a unit, whereas a scalar has a number only.
A vector has direction, whereas a scalar does not have direction.
A vector has mass, whereas a scalar does not have mass.
A vector measures speed, whereas a scalar measures velocity.
A vector does not have a number, whereas a scalar does have a number.
4. Which of the following statements about motion graphs is incorrect?
a.
b.
c.
d.
e.
The slope of a position-time graph gives velocity.
The slope of a velocity-time graph gives acceleration.
The area under a velocity-time graph gives displacement.
The area under a position-time graph gives velocity.
The slope of an acceleration-time graph is zero when there is uniform velocity.
5. Robert left home and went for a jog. He jogged 2.0 km [N], and then 3.0 km [S]
followed by 4.0 km [N]. What is Robert’s final position from home?
a.
b.
c.
d.
e.
0.0 km
3.0 km [N]
9.0 km [N]
3.0 km [S]
9 km [S]
6. If a box has a weight of 1000 N, its mass is:
a.
b.
c.
d.
e.
1000 kg
102 kg
9800 kg
1000 kg [down]
unrelated to its weight, but dependent on the amount of matter
7. A 30 kg box is lifted from the ground to a height of 1.5 m. The work done is:
a.
b.
c.
d.
e.
441 J
45 J
20 J
4.6 J
294 J
8. If the amount of friction present in a moving machine decreases:
a.
b.
c.
d.
e.
The AMA decreases (in relation to the IMA) and the percent efficiency decreases.
The AMA increases (in relation to the IMA) and the percent efficiency increases.
The AMA increases (in relation to the IMA) and the percent efficiency decreases.
The AMA decreases (in relation to the IMA) and the percent efficiency increases.
More information is required.
9. The turning effect on a rigid bar around a pivot point is referred to as
a.
b.
c.
d.
e.
applied force
tension
torque
normal force
effort
10. A moveable pulley system has three support strings pulling up on the moving pulley. The ideal
mechanical advantage of this system is:
a. 1
b. 3
c. 4
d. 50%
e. 100%
11. If a 1.5 kg chicken is running with a speed of 10.0 m/s, its kinetic energy is:
a.
b.
c.
d.
e.
150 J
7.5 J
75 J
6.7 J
15 J
12. A ball is dropped from a height of 3.0 m. As it falls:
a.
b.
c.
d.
e.
Its gravitational potential energy increases and its kinetic energy increases.
Its gravitational potential energy increases and its kinetic energy decreases.
Its gravitational potential energy decreases and its kinetic energy increases.
Its gravitational potential energy decreases and its kinetic energy decreases.
There is no change to either its gravitational potential or its kinetic energy.
13. If done long enough, rubbing two sticks together can produce enough heat to start
a fire. If
100.0 J of thermal energy is required to start the fire and the average frictional force between the
sticks is 20.0 N, the distance the sticks must slide past one other is:
a.
b.
c.
d.
e.
2.00 m
5.00 m
10.0 m
100.0 m
3
2.00 × 10 m
14. The amount of energy used by a 100 W light bulb in 1 minute is:
a.
b.
c.
d.
e.
6000 J
100 J
600 J
1.7 J
60 000 J
15. Which of the following energy transformations best describes the operation of a battery powered
flashlight?
a.
b.
c.
d.
e.
electrical energy --> thermal energy --> kinetic energy
nuclear energy --> potential energy --> chemical energy
thermal energy --> elastic potential energy --> electrical energy
radiant energy --> electrical energy --> chemical potential energy
chemical energy --> electrical energy--> radiant energy
16. If two 100 Ω resistors are placed in parallel, their total resistance changes by what factor
compared to the same two 100 Ω resistors placed in series with each other:
a.
b.
c.
d.
e.
the same
twice
half
one quarter
1/200
17. How will the current in the first ammeter compare with the reading in the second?
a.
b.
c.
d.
e.
A1 has a current reading while A2 has a reading of zero.
A1 and A2 are equal.
A1 is less than A2.
A1 is greater than A2.
More information is necessary.
18. What is the direction of the magnetic field inside and outside a bar magnet?
Inside the Magnet
a. north to south
b. north to south
c. south to north
d. south to north
e. field does not exist
Outside the Magnet
north to south
south to north
north to south
south to north
north to south
19. If the compass in the diagram below is placed directly ABOVE the conductor when the switch is
closed, in what direction will the compass point?
a.
b.
c.
d.
e.
North
South
East
West
Current has no effect on the compass.
20. In a single coil DC motor, when is the direction in a coil reversed?
a.
b.
c.
d.
e.
after each 1/2 revolution
after each 1/4 revolution
after each 3/4 revolution
after each revolution
Never. The direction of the current does not change in the coil.
21. When the cross-sectional area of a fluid-carrying pipe increases, the flow speed of the fluid will:
a.
b.
c.
d.
e.
increase
decrease
stay the same
change unpredictably
It depends on viscosity.
22. Which of the following substances would likely have the least laminar flow?
a.
b.
c.
d.
e.
water
cool honey
warm honey
vegetable oil
molasses
23. A 2-cylinder system is constructed so that the output cylinder’s area is 5 times bigger than the
area of the input cylinder. How does the input force compare to the output force?
a.
b.
c.
d.
th
The input force is 1/5 the output force.
The input force is 5 times the output force.
th
The input force is 1/10 the output force.
The input force is 10 times the output force.
24. Bernoulli’s Principle states that:
a.
b.
c.
d.
e.
Pressure is high when flow rate is high.
Pressure is low when flow rate is high.
Pressure is the same regardless of flow rate.
Pressure increases if force increases.
The same force on a larger area results in less force per area.
2
25. The force applied to an object that experiences 30 kPa of pressure over 0.02 m is:
a.
b.
c.
d.
600 N
0.6 N
1500 N
0.0007 N