Name: ___________________________________ Period: ______ Date: ________________
Ch 10.3 & 11Forces: Pre-Test
Match each definition on the left with its correct term on the right.
1. _____ the total amount of momentum before
a collision is the same as the total
amount afterwards
2. _____ for every action there is an equal and
opposite reaction
3. _____ net (total) force = 0, no change in
motion
4. _____ force of objects rubbing together when
they move; can be rolling or sliding
5. _____ an arrow used to show the magnitude
(amount) and direction of a force
6. _____ force that pulls things towards the
center of an object, proportional
to mass
7. _____ when an object is moving only due to
the force of gravity, can only happen
in outer space or a vacuum
8. _____ combination of horizontal and vertical
motion that makes things move in
an arc (parabola)
9. _____ force that opposes motion, air resistance
is an example
10. _____ an action on an object that changes its
motion
11. _____ mass x acceleration due to gravity,
changes when you go to different
planets
12. _____ tendency of an object to not want to change
A. ag
B. balanced force
C. elastic collision
D. force
E. free fall
F. friction
G. gravity
H. inelastic collision
I. inertia
J. kinetic friction
K. Law of Conservation
of Momentum
L. Law of Universal Gravity
M. momentum
N. net force
O. Newtons
P. Newton’s 1st Law of Motion
Q. Newton’s 2nd Law of Motion
R. Newton’s 3rd Law of Motion
S. projectile motion
T. resultant
U. static friction
V. terminal velocity
W. unbalanced force
X. vector
Y. weight
motion
13. _____ F=ma; acceleration on an object depends on the net force acting on it and
its mass
14. _____ when two objects hit and do not stick together, they bounce off
15. _____ Gm1m2/d2; the force of gravity between two objects depends on their
masses and the distance between them
16. _____ when the acceleration due to gravity is balanced by air resistance; you
won’t go any faster as you fall
17. _____ the sum of all forces acting on an object
18. _____ force between surfaces that are not moving
19. _____ 10.0 m/s2
20. _____ units that force is measured in; equals 1kg x 1m/s2
21. _____ an object at rest stays at rest and an object in motion stays in motion
unless acted upon by an unbalanced force
22. _____ p = mv
23. _____ in a drawing of forces, the sum of all the force acting on an object
24. _____ objects collide and stick together
25. _____ when an object is changing speed or direction or both it is experiencing this
26. How can you tell if the forces on an object are balanced? How will it be moving?
27. How can you tell if the forces on an object are unbalanced? How will it be
moving?
You drop a golf ball and a bowling ball from the top of your house at the same exact
time.
28. Which one will hit the ground first? Why?
29. What forces affect how fast something falls?
30. Which object has more inertia?
You shoot a golf ball and bowling ball from a cannon.
31. Which would accelerate faster? Why?
32. What forces affect how fast something accelerates?
33. When you are in a car that turns to the right, why does your body lean to the
left? Which of Newton’s Laws of Motion applies here?
34. If you drop a bowling ball from 100 feet high on the Moon and Earth, will it fall
faster on the Moon, on Earth, or at the same rate in either place? Why?
35. ________________ A girl has a mass of 40 kg. What is her weight? Explain your
answer.
36. ________________ You push a grocery cart with a certain amount of force. The
grocery cart has a mass of 20 kg and when you push it, you
accelerate it at a rate of 2.0 m/s2. With what force did you
push the cart? Show your work below.
37. What forces are acting on the grocery cart in the previous problem? Draw a
diagram and label the forces that are acting and use arrows to show the
direction that they are acting. Are all of these forces the same strength or are
some stronger than others?
38. While being pushed in a rolling chair at a constant speed, you tilt your head up
and spit your gum out of your mouth, straight up in the air. If you continue to
move at this constant speed, could you catch the gum in your mouth again
without changing your position? Or will the gum land ahead of you? Or will
the gum land behind you?
39. What forces are acting on the person on the chair in the previous problem? Draw
a diagram and label the forces that are acting and use arrows to show the
direction that they are acting. Are all of these forces the same strength or are
some stronger than others?
40. You punch a wall really, really hard. Is more force applied to the wall or to your
fist during the punch? Why is this?
41. What are the action and reaction force pair in the previous problem?
42. Student A pushes a refrigerator with 300 N of force and student B pushes the
refrigerator the opposite way with 100 N of force at the same time. Draw and
label arrows that are to scale that represent the forces from each student and
one that represents the result of the two forces combined.
Two identical toy cars collide. Describe each cars final velocity if…
43. they are headed toward one another at the same speed and bounce off each
other. (You may want to draw a picture)
44. they are headed toward one another at the same speed and stick together.
(You may want to draw a picture)
45. they are headed toward one another at different speeds and they bounce off
each other. (You may want to draw a picture)
46. they are headed toward one another at different speeds and they stick
together. (You may want to draw a picture)
47. How is the law of Conservation of Momentum shown in the above problems about
the toy cars?
48. __________________ A 1000 kg car is going 15 m/s. What is its momentum?
49. __________________ Who has more momentum: a 75 kg swimmer going 4 m/s or a
100 kg fullback going 3 m/s? Explain.
Answer key__
Name: __
Period: ______ Date: ________________
Ch 10.3 & 11Forces: Pre-Test
Match each definition on the left with its correct term on the right.
K__ the total amount of momentum before
1. __
a collision is the same as the total
amount afterwards
A. ag
B. balanced force
C. elastic collision
opposite reaction
D. force
E. free fall
motion
F. friction
G. gravity
they move; can be rolling or sliding
H. inelastic collision
I. inertia
(amount) and direction of a force
J. kinetic friction
K. Law of Conservation
center of an object, proportional
to mass
of Momentum
L. Law of Universal Gravity
M. momentum
R__ for every action there is an equal and
2. __
B__ net (total) force = 0, no change in
3. __
J__ force of objects rubbing together when
4. __
X__ an arrow used to show the magnitude
5. __
G__ force that pulls things towards the
6. __
E__ when an object is moving only due to
7. __
the force of gravity, can only happen
in outer space or a vacuum
N. net force
O. Newtons
P. Newton’s 1st Law of Motion
motion that makes things move in
an arc (parabola)
Q. Newton’s 2nd Law of Motion
R. Newton’s 3rd Law of Motion
S. projectile motion
is an example
T. resultant
U. static friction
motion
V. terminal velocity
W. unbalanced force
S__ combination of horizontal and vertical
8. __
F__ force that opposes motion, air resistance
9. __
D__ an action on an object that changes its
10. __
Y__ mass x acceleration due to gravity,
11. __
I
changes when you go to different
planets
X. vector
Y. weight
12. __ __ tendency of an object to not want to change motion
Q__ F=ma; acceleration on an object depends on the net force acting on it and
13. __
its mass
C__ when two objects hit and do not stick together, they bounce off
14. __
L__ Gm1m2/d2; the force of gravity between two objects depends on their
15. __
masses and the distance between them
V__ when the acceleration due to gravity is balanced by air resistance; you
16. __
won’t go any faster as you fall
N__ the sum of all forces acting on an object
17. __
U__ force between surfaces that are not moving
18. __
A__ 10.0 m/s2
19. __
O__ units that force is measured in; equals 1kg x 1m/s2
20. __
P__ an object at rest stays at rest and an object in motion stays in motion
21. __
unless acted upon by an unbalanced force
M__ p = mv
22. __
T__ in a drawing of forces, the sum of all the force acting on an object
23. __
H__ objects collide and stick together
24. __
W__ when an object is changing speed or direction or both it is experiencing
25. __
this
26. How can you tell if the forces on an object are balanced? How will it be moving?
It will not be accelerating…that is, it will either
be at rest or have a constant velocity (both speed
and direction)
27. How can you tell if the forces on an object are unbalanced? How will it be
moving?
It will be accelerating; changing either its speed
or direction or both
You drop a golf ball and a bowling ball from the top of your house at the same exact
time.
28. Which one will hit the ground first? Why?
They will hit at the same time (especially
if ignoring air resistance) because all objects fall
at the same rate…9.8m/s2.
The bowling ball has more mass, so
gravity pulls more, but also more inertia and
their effects “cancel” each other out.
29. What forces affect how fast something falls?
Gravity and air resistance
30. Which object has more inertia?
Bowling ball because it has more mass
You shoot a golf ball and bowling ball from a cannon.
31. Which would accelerate faster? Why?
Golf ball. Given the same force, it has a
smaller mass so a bigger acceleration
32. What forces affect how fast something accelerates?
Net force acting on it…sum of all the
forces. If the sum/net force is 0, it still moves,
it just won’t accelerate (change speed or
direction)
33. When you are in a car that turns to the right, why does your body lean to the
left? Which of Newton’s Laws of Motion applies here?
Newton’s First Law of Motion
You don’t lean to the left…you are an
object in motion and you stay in motion at the
same speed/direction until acted upon by an
unbalanced force…the seat belt, I hope….
34. If you drop a bowling ball from 100 feet high on the Moon and Earth, will it fall
faster on the Moon, on Earth, or at the same rate in either place? Why?
Earth…has more mass, therefore more
gravity.
400N___ A girl has a mass of 40 kg.
35. ___
What is her weight? Explain your
answer.
Weight = mass x g (acceleration due to
gravity 9.8 m/s2)
400N (I rounded to 10.0 m/s2 and weight
is a force, so its measured in N)
40 N_____ You push a grocery cart with a certain amount of force.
36. ____
The
grocery cart has a mass of 20 kg and when you push it, you
accelerate it at a rate of 2.0 m/s2. With what force did you
push the cart? Show your work below.
F=ma
F = 20 kg x 2.0 m/s2
F = 40 N
37. What forces are acting on the grocery cart in the previous problem? Draw a
diagram and label the forces that are acting and use arrows to show the
direction that they are acting. Are all of these forces the same strength or are
some stronger than others?
normal
friction
applied
g
Note: applied is greater than friction.
Since there’s acceleration forward, the
forces are unbalanced.
38. While being pushed in a rolling chair at a constant speed, you tilt your head up
and spit your gum out of your mouth, straight up in the air. If you continue to
move at this constant speed, could you catch the gum in your mouth again
without changing your position? Or will the gum land ahead of you? Or will
the gum land behind you?
Yes, you can. The gum is moving forward
at the same speed you are (object in motion)
and the up/down motion has no effect on the
forward motion.
39. What forces are acting on the person on the chair in the previous problem? Draw
a diagram and label the forces that are acting and use arrows to show the
direction that they are acting. Are all of these forces the same strength or are
some stronger than others?
normal
friction
applied
g
Note: friction and applied are the same.
Since there’s constant speed, (no acceleration)
the forces are balanced.
40. You punch a wall really, really hard. Is more force applied to the wall or to your
fist during the punch? Why is this?
Same to both. For every action there is
an equal and opposite reaction. Your hand
moves more because it has less inertia (1st Law)
or because with the same force, it has less mass
so accelerates more (2nd Law)
41. What are the action and reaction force pair in the previous problem?
Action…you hit the wall
Reaction…the wall “hits” back.
Note: the force pairs happen:
 At the same time
 In the same magnitude (amount)
 In opposite directions
 On different objects (wall, you)
300 N of force and student B pushes the
refrigerator the opposite way with 100 N of force at the same time. Draw
42. Student A pushes a refrigerator with
and label arrows that are to scale that represent the forces from each student
and one that represents the result of the two forces combined.
My scale: 1 block = 25 N.
Result is 200N in direction of 300 N
Two identical toy cars collide. Describe each cars final velocity if…
43. they are headed toward one another at the same speed and bounce off each
other. (You may want to draw a picture)
bounce back in opposite directions at
same speeds as began.
Before:
After:
44. they are headed toward one another at the same speed and stick together.
(You may want to draw a picture)
stick and don’t move
Before:
After:
45. they are headed toward one another at different speeds and they bounce off
each other. (You may want to draw a picture)
bounce off, change velocities (directions
and speeds)
Before:
After:
46. they are headed toward one another at different speeds and they stick
together. (You may want to draw a picture)
stick together move slowly (at ½
difference in speeds) in direction of faster one
Before:
After:
47. How is the law of Conservation of Momentum shown in the above problems about
the toy cars?
The system is both cars (not just one). When
you add their momenta up before and after and
compare, you get the same amount.
20000 kg x m/s ___ A 1000 kg car is going 15 m/s. What is its
48. ___
p = mv
momentum?
p = 1000 x 15
p = 15000
p = 20000 kg x m (1 sig fig)
s
same!__ Who has more momentum: a 75 kg swimmer going 4 m/s or a
49. ___
100 kg fullback going 3 m/s? Explain.
They are the same!
Swimmer … p = mv
p = 75 x 4
p = 300 kg x m
s
Fullback … p = mv
p = 100 x 3
p = 300 kg x m
s