Download Unit B Practice Unit Exam

Physics 20 Unit B: Dynamics
Practice Exam:
YOUR UNIT B EXAM IS WORTH 12% OF YOUR OVERALL MARK!
YOU WILL HAVE SOME EXTRA TIME BEFORE CLASS IN THE MORNING
(BLOCK 1) OR AT LUNCH (BLOCK 2) IF YOU WOULD LIKE EXTRA TIME. NO
EXTRA TIME CAN BE ALLOWED AFTER THE BLOCK!
BRING A PENCIL AND CALCULATOR!
The following is a practice exam to for your use in studying. It has approximately the same
number of multiple choice, numerical response and written response questions as your real
exam. It is written at as close to the same difficulty as possible and contains many of the same
concepts. It is not by any means an exhaustive list of what to study, but it is a good start. It is
wise to use it in a test-like environment (quiet, isolated from other people) and to complete it in a
period of time similar to how long it you will get for your real exam Answers are printed below.
NR 1 = 425
1. A
2. A
3. B
4. B
5. C
6. B
7. B
8. D
9. B
NR 2 = 3.46
10. A
11. C
12. C
NR 3 = 41
13. D
14. D
15. D
16. D
17. D
18. D
19. C
NR 4 = 0.31
NR 5 = 3.68
WR 1 = 1.4 m/s2
WR 2 = 1.15 x 105 km
11/6/2013
P20 Unit B Practice Unit
Exam
Name: ____________
Date: ____________
MC and NR: Please place all answer on the answer sheet provided. (1 mark each)
Use the following information to answer the next question.
1.
2.
3.
NR 1
Physics Terms
kilograms
5.
weight
newtons
4.
vector
scalar
6.
inertia
Forces are ______ quantities, measured in ________. One example of a force is the
concept of ______.
The numbers above that best complete this statement, in the correct order, are ________.
Record your 3-digit answer on the answer sheet provided.
1. A 3.50 x 103 kg truck starts from rest and accelerates for 32.5 s. If the truck travels with
constant acceleration for a distance of 1.15 km, what force is exerted on the truck during this
time interval?
a) 7.62 x 103 N
b) 3.43 x 104 N
c) 1.2 x 105 N
d) 2.48 x 105 N
2. A force of 65.0 N is exerted on a 40.0 kg object and it accelerates at a rate of 1.5 m/s2 over a
rough floor. What is the force of friction acting on the object?
a) 5.0 N
b) 6.1 N
c) 7.6 N
d) 27 N
3. Inertia may be defined as the tendency of an object to
a) begin motion in other objects at rest
b) keep its state of rest or uniform motion
c) change the motion of other objects in motion
d) slow down to rest after motion or remain at rest
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11/6/2013
4. A sled (m = 10 kg) is given a push along a horizontal surface. The force applied to the sled is
50 N. The sled comes to rest after 2.5 s. The initial velocity of the sled was
a) 2.0 m/s
b) 13 m/s
c) 20 m/s
d) 98 m/s
5. A student applies a force, F, to a box. The box accelerates at a magnitude of a. If the
magnitude of the force doubles while the mass of the box triples, the new acceleration on the box
will be
a) 2a
b) 3a
c) 2/3a
d) 3/2a
6. Determining the mass of an object by measuring the force acting on an object and the resulting
acceleration allows one to determine
a) the gravitational mass
b) the inertial mass
c) the relativistic mass
d) the normal mass
Use the following information to answer the next two questions.
A box of golf balls falls on an inclined plane in a packing facility. The box has a mass of 2.10
kg and the incline is at 15.0 to the horizontal. The box hits the plane and begins to slide down
towards the shipping station at a constant speed.
7. The force of gravity and normal force acting on the box are, respectively,
a) 20.6 N, 20.6 N
b) 20.6, 19.9 N
c) 19.9 N, 20.6 N
d) 20.6 N, 5.33 N
8. In order for the box to slide at a constant speed, the __i__ force must be equal and opposite of
the __ii__ force. The row that best completes the statement is
a)
b)
c)
d)
i
frictional
frictional
parallel
parallel
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ii
gravitational
normal
gravitational
frictional
11/6/2013
Use the following information to answer the next two questions.
During an experiment, a 1.20 kg lab cart is accelerated on a low-friction table by a
0.500 kg mass moving straight down as shown. Assume any friction in the system is
negligible.
9. The acceleration of the lab cart is
a) 1.70 m/s2
b) 2.89 m/s2
c) 4.10 m/s2
d) 9.81 m/s2
NR 2
The tension in the string is ____________ N.
Record your answer to 3 digits on the answer sheet provided.
Use the following information to answer the next question.
LD’s interactive whiteboard breaks down one day, so he has to make this crappy diagram of
a one-pulley system by hand. The students are not impressed with his artistic capabilities.
10. If LD’s crappy pulley systems existed in real life, the acceleration of the system would be
a) 2.3 m/s2
b) 3.8 m/s2
c) 6.1 m/s2
d) 9.8 m/s2
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11. The statement below that does not correspond to a field theory of gravity is
a) gravitational fields point towards the centre of objects.
b) gravitational fields extend infinitely.
c) the strength of gravitational fields can be determined by the relative size of the field line.
d) gravitational fields are created by any object with mass.
12. Gravitational field strength is represented by the variable __ i__ and is said to be __ii__. The
row that best completes the statement is
a)
b)
c)
d)
i
g
Fg
g
G
ii
constant throughout the universe.
approximately the same across Earth’s surface.
approximately the same across the Earth’s surface.
constant throughout the universe
Use the following information to answer the next question.
A satellite is in orbit around the Earth. Some possible statements concerning the gravitational
field produced by the Earth in this system are numbered below.
The gravitational field of the Earth is…
1.
2.
3.
4.
NR 3
dependant on the mass of the Earth
dependant on the mass of the satellite
directly proportional to the separation between the Earth and satellite.
inversely proportional to the square of the separation between the Earth and satellite.
Two true statements concerning the gravitational field produced by the Earth are __
and __.
Record your 2 digit answer on the answer sheet provided.
13. As the separation between two bodies triples, force of gravity between them
a) decreases by a factor of 3
b) increases by a factor of 6
c) increases by a factor of 9
d) decreases by a factor of 9
14. As the mass of the body producing a gravitational field doubles, G
a) doubles
b) halves
c) quadruples
d) remains unchanged
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15. The distance between the Earth and Sun is approximately 149 600 000 km, or 1 astronomical
unit (1 au). The force of gravity acting on the Earth due to the Sun is F. If the Sun were 3 times
more massive than it is now and the Earth-Sun distance increased to 7 au, the new force of
gravity acting on the Earth due to the Sun would be
a) F
b) 7/3 F
c) 3/7 F
d) 3/49 F
16. A student weighing 735 N steps into an elevator and pushes the button to go up. If the
elevator accelerates at 3.5 m/s2 for 3.0 s, what is the mass of the student during this time?
a) 48 kg
b) 56 kg
c) 68 kg
d) 75 kg
17. A student weighing 735 N steps into an elevator and pushes the button to go up. If the
elevator accelerates at 3.5 m/s2 for 3.0 s, what is the apparent weight of the student during this
time?
a) -262 N
b) -473 N
c) -735 N
d) -998 N
18. An elevator with a mass of 1.0 x 103 kg accelerates upward at 4.0 m/s2. What is the tension
in the cable that pulls the elevator?
a) 4.0 x 103N
b) 5.8 x 103 N
c) 9.8 x 103 N
d) 1.4 x 104 N
19. After watching a video of an astronaut orbiting the Earth in a space station a student claims
the astronaut is “weightless”. This claim is incorrect because
a) the weight of an object never changes, whether on the surface of Earth or in orbit around it.
b) the astronaut still has weight, it is just so small, it is unnoticeable.
c) the astronaut is actually in a state of perpetual free fall, hence the apparent “weightlessness”.
d) the student bases all of their claims on that movie “Gravity”.
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NR 4
In an experiment, a student exerts a force of 15.0 N on a 5.00 kg oak block to keep
it moving at a constant velocity on a table. What is the coefficient of kinetic
friction between the block and the table?
Record your answer to 3 digits on the answer sheet provided.
NR 5
The mass of Mercury is 0.055 times that of Earths and its radius is 0.3829 times
that of Earths. Determine the gravitational field strength on Mercury.
Record your answer to 3 digits on the answer sheet provided.
Written Response: show all work to receive full marks.
1. LD is taking his two children for a sled ride down Hamburger Hill. The LD family sled is
made of plastic and a coefficient of kinetic friction of 0.055 exists between the sled and the
snow. Additionally, the sled has breaks which provide a maximum breaking force of 96.43 N. If
the combined mass of LD’s children and the sled is 22.7 kg and the hill makes a 20.0 incline to
the horizontal, what is the acceleration of the sled when the breaks are applied? (6 marks)
2. At what distance from the Earth’s surface, in km, would the moon experience a gravitational
pull that is 10 times greater than it currently is? The distance between the Earth and Moon, centre
to centre, is 384 400 km. (3 marks)
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