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Review Problems –Physics Midterm Exam
Name
Date
Pd
Constant Velocity
2
3
4
Motion Map
Written Description
v vs. t graph
x vs. t graph
1
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
6
7
8
Object moves with
constant positive
velocity for 4 seconds.
Then, it stops for 2
seconds and returns to
the initial position in 2
seconds.
Object A starts 10m to
the right of the origin
and moves to the left at
2 m/s.
Object B starts at the
origin and moves to the
right at 3m/s.
Motion Map
Written Description
v vs. t graph
x vs. t graph
5
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
Date
Constant Acceleration
+
v (m/s)
1. A poorly tuned Geo Metro can accelerate from rest to a speed of
28 m/s in 20 s.
a) What is the average acceleration of the car?
b) What distance does it travel in this time?
t (s)
-
+
v (m/s)
2. At t = 0 a car has a speed of 30 m/s. At t = 6 s, its speed is 14 m/s.
What is its average acceleration during this time interval?
t (s)
-
v (m/s)
3. A bear spies some honey and takes off from rest, accelerating at a rate of 2.0 m/s2.
+ the treat?
If the honey is 16 m away, how fast will his snout be going when it reaches
+
(
s
)
v (m/s)
4. A bus moving at 20 m/s (t = 0) slows at a rate of 4 m/s each second.
a) How long does it take the bus to stop?
b) How far does it travel while braking?
t (s)
t (s)
-
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
v (m/s)
5. A physics student skis down a hill, accelerating at a constant 2.0 m/s2. +
If it takes her 15 s to reach the bottom, what is the length of the slope?
t (s)
-
v (m/s)
(
+ uniformly increases his speeds
6. A dog runs down his driveway with an initial speed of 5 m/s for 8 s, then
)
to 10 m/s in 5 s.
a) What was his acceleration during the 2nd part of the motion?
b) How long is the driveway?
t (s)
-
v (m/s)
7. A mountain goat starts a rock slide and the rocks crash down the slope 100 m.
+
If the rocks reach the bottom in 5 s, what is their acceleration?
t (s)
-
v (m/s)
8. A car whose initial speed is 30 m/s slows uniformly to 10 m/s in 5 seconds.
+
a) Determine the acceleration of the car.
b) Determine the distance it travels in the 3rd second
(t = 2s to t = 3s).
t (s)
-
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
Name
Date
Pd
2-D Kinematics
In all the problems below, draw a diagram to represent the situation. Identify the knowns and unknowns
and label clearly.
Part I - use g = 10m/s2
1. The movie "The Gods Must Be Crazy" begins with a pilot dropping a bottle out of an airplane. It is
recovered by a surprised native below, who thinks it is a message from the gods. If the plane from
which the bottle was dropped was flying at a height of 500m, and the bottle lands 400m horizontally
from the initial dropping point, how fast was the plane flying when the bottle was released?
2. Suppose that an airplane flying 60 m/s, at a height of 300m, dropped a sack of flour. How far from the
point of release would the sack have traveled when it struck the ground?
3. In many locations, old abandoned stone quarries have become filled with water once excavating has
been completed. While standing on a quarry wall, a boy tosses a piece of granite into the water below.
If he throws the ball horizontally with a velocity of 3.0 m/s, and it strikes the water 4.5 m away, how
high above the water is the wall?
4. Tad drops his bowling ball out the car window 1.0 m above the ground while traveling down the road at
18 m/s. How far, horizontally, from the initial dropping point will the ball hit the ground? If the car
continues to travel at the same speed, where will the car be in relation to the ball when it lands?
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
Part II
5. A student finds that it takes 0.20s for a ball to pass through photogates placed 30 cm apart on a level
ramp. The end of the ramp is 92 cm above the floor.
Where should a coin be placed so that the ball strikes it directly on impact with the ground?
6. Suppose now that the same ball, released from the same ramp (92 cm high) struck a coin placed 25 cm
from the end of the ramp.
a) What was the ball's horizontal velocity?
b) How long did it take for the ball to pass through the photogates?
Challenge problems
7. Suppose a metal sphere is launched up a ramp with Vi = 1.5 m/s. The end of the ramp is 1.20 m above
the floor. Calculate the range of the sphere.
Vi
20
8. Now suppose that the ramp is tilted downwards as shown below.
Vi
15
Suppose that the sphere leaves the ramp at 1.5 m/s. The bottom of the ramp is 0.90 m above the floor.
Calculate the range of the sphere.
Name
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
Date
Pd
Forces
For each of the problems below, carefully draw a force diagram of the system before attempting to solve
the problem.
1. Determine the tension in each cable in case A and case B.
Case A
5 kg
Case B
5
2. Determine tension in each cable. (Hint: There is more than one way to define the system.)
3. The object hung from the cable has a weight of 25 N. Write the equation for the sum of the forces in the
y-direction. What is the tension in the cable?
Repeat the problem above with a 5° angle. How does the tension compare?
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
4. The cable at left exerts a -30 N force.
30
T2
a. Write the equation for the sum of the forces in the x-direction. What is
the value of T2?
T1
b. Write the equation for the sum of the forces in the y-direction. What is the force of gravity acting on the
ball?
5. The box on the frictionless ramp is held at rest by the tension force. The mass of the box is
20 kg. What is the value of the tension force?
T
What is the value of the normal force?
6. In the system below the pulley and ramp are frictionless and the block is in static equilibrium. What is
the mass of the block on the ramp?
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
7. A man pulls a 50 kg box at constant speed across the floor. He applies a 200 N force at an angle of 30°.
a. Sum the forces in the x-direction. What is the value of the frictional force opposing the motion?
b. Sum the forces in the y-direction. What is the value of the normal force?
8. A man pushes a 2.0 kg broom at constant speed across the floor. The broom handle makes a 50° angle
with the floor. He pushes the broom with a 5.0 N force.
a. Sum the forces in the y-direction. What is the value of the normal force?
b. Sum of the forces in the x-direction. What is the value of the frictional force opposing the motion?
c. If the frictional force were suddenly reduced to zero, what would happen to the broom?
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
More Forces
1. Suppose a hanging 1.0 kg lab mass is attached to a 4.0 kg block on the table.
a. If the coefficient of kinetic friction, µk is 0.20., what is the acceleration of the block?
b. What would be the minimum value of the coefficient of static friction, µs, in order for the block to
remain motionless?
2. A block weighing 300. N is moved at constant speed over a horizontal surface by a force of 50. N
applied parallel to the surface.
a. Construct a force diagram for the block.
b. What is the coefficient of kinetic friction?
c. What would be the acceleration of the block if k = 0?
3. A 100. N force is applied to a 50. kg crate resting on a level floor. The coefficient of kinetic friction is
0.15.
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
a. Draw a force diagram to represent this situation.
b. What is the acceleration of the crate?
4. In the situation described above, the coefficient of static friction, s = 0.25. Is the
100. N force sufficient to cause the crate to accelerate? Draw a force diagram, then explain why or why
not.
5. A 10 kg block is allowed to slide down a ramp with k = 0.15.
a. What is the value of the frictional force opposing the block's slide down the ramp?
b. What is the acceleration of the block?
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
Energy
1. A 60 kg box is lifted by a rope a distance of 10 meters straight up at constant speed. How much power
is required to complete this task in 5 seconds?
2. Hulky and Bulky are two workers being considered for a job at the UPS loading dock. Hulky boasts
that he can lift a 100 kg box 2.0 meters vertically, in 3.0 seconds. Bulky counters with his claim of
lifting a 200 kg box 5.0 meters vertically, in 20 seconds.
Which worker has a greater power rating?
3. A 1994 Ford Mustang is driving down a road with a constant speed of 30 m/s. The engine must exert a
5000 N force to maintain this speed.
a. What is the power rating of the engine?
b. How does the Mustang's power rating compare to the 220 hp Dodge Stealth engine
(1 hp = 746 W)?
©Modeling Workshop Project 2006
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Unit II ws5 v3.0
Review Problems –Physics Midterm Exam
4. An 82 kg hiker climbs Mt. Humphrey near Flagstaff. During a two hour period, the hiker's vertical
elevation increases by 540 meters.
a. Calculate the climber's ∆Eg.
b. Find the power generated to increase the hiker's Eg.
5. How long would it take a 7.5 KW motor to raise a 500 kg piano to an apartment window 10 meters
above the ground?
6. The trains on the Viper are raised from 10 m above ground at the loading platform to a height of 60 m at
the top of the first hill in 45 s. Assume that the train (including passengers) has a mass of 2500 kg.
Ignoring frictional losses, what power motor would be required to accomplish this task?
7. Your electric utility company sends you a monthly bill informing you of the number of kilowatt-hours
you have used that month.
a. Is the utility charging you for energy or power? Explain.
b. How many joules does your 1600W blow drier transfer if you dry your hair in 5.0 min?
©Modeling Workshop Project 2006
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Unit II ws5 v3.0