True/False Indicate whether the
statement is true or false.


1.

A speed that does not vary is called average speed.


2.

Acceleration is defined as the rate of change of position.


3.

The combination of all forces acting on an object is the net force.


4.

Velocity changes when the direction of motion changes.


5.

The more mass an object has, the greater its inertia is.


6.

Work equals force times distance (W = F ´ d).


7.

Newton's third law says that an object in motion is slowed down by
gravity.


8.

Friction always acts in a direction opposite of motion.


9.

When you walk, you push on the sidewalk, and the sidewalk pushes on you with
equal force.


10.

The relationship of force and acceleration of an object is explained using
Newton’s first law of motion.

Multiple Choice Identify the
choice that best completes the statement or answers the question.


11.

A soccer ball takes 20 s to roll 10 m. What is the average speed of the soccer
ball?
a.  200 m/s  c.  2 m/s  b.  5 m/s  d.  0.5 m/s 


12.

When an object is at rest, what is its speed?
a.  2 m/s  c.  1 m/s  b.  3 m/s  d.  0 m/s 


13.

Which describes how velocity changes with time?
a.  acceleration  c.  gravity  b.  average speed  d.  inertia 


14.

A person in a headon car collision who is not wearing a seat belt continues to
move forward at the original speed of the car because of ____.
a.  friction  c.  gravity  b.  inertia  d.  weight 


15.

If you want to calculate the acceleration of a car, you should ____ the change
in speed of the car by the time interval.
a.  add  c.  divide  b.  decrease  d.  multiply 


16.

What is the term for speed at any instant in time?
a.  instantaneous speed  c.  constant speed  b.  variable speed  d.  average speed 


17.

Newton’s first law of motion states that an object stays at rest unless
a(n) ____ acts on it.
a.  balanced force  c.  gravitational force  b.  unbalanced force  d.  strong force 


18.

Which one of the following objects has the greatest inertia?
a.  baseball  c.  pencil  b.  bowling ball  d.  toothpick 


19.

A force is which one of these?
a.  a push  c.  a push or pull  b.  a pull  d.  none of these 


20.

Force is measured in which units?
a.  kilograms  c.  newtons  b.  degrees  d.  m/s^{2} 


21.

For an ideal machine, the work in is equal to ____.
a.  a fraction of the work out  c.  the work out  b.  twice the work
out  d.  half the work
out 


22.

____ is done only when an object moves in the direction of the applied
force.
a.  Friction  c.  Effort  b.  Work  d.  Inertia 


23.

A force is exerted on a box and an equal and opposite force is exerted by the
box. What explains this?
a.  conservation of energy  c.  Newton’s second law of motion  b.  Newton’s first
law of motion  d.  Newton’s third law of motion 


24.

A(n) ____ is a rod or plank that pivots about a fixed point.
a.  wedge  c.  pulley  b.  axle  d.  lever 


25.

According to Newton’s second law of motion, ____.
a.  a = F_{net}/m  c.  a =
m/F_{net}  b.  a = m X F_{net}
X s  d.  a = s
X m 

Matching



Match the units with the descriptions below.


26.

the unit of force


27.

the unit of average speed


28.

the unit of work


29.

the unit of acceleration


30.

the unit of distance



Match the terms with the statements below. a.  pulley  d.  Newton’s second law  b.  wedge  e.  Newton’s third law  c.  Newton’s first
law 


31.

The harder you pedal a bicycle, the faster it will go.


32.

the main reason a person can jump off the ground


33.

your front teeth


34.

the cord on a window blind


35.

A hockey puck will slide across ice for a long time when hit.

Completion Complete each
statement.


36.

According to Newton’s Third Law, forces always occur in equal but
____________________ pairs.


37.

The ____________________ is the combination of all the forces acting on an
object.


38.

____________________ measures the quantity of matter in an object.


39.

The acceleration of an object can be shown on a(n) ____________________
graph.


40.

Machines can change the ____________________ of the force you apply and the
____________________ of the force.


41.

The force that resists motion between two objects that are in contact with each
other is ____________________.


42.

According to Newton’s first law of motion, an object moving in a straight
line at constant speed will continue doing that unless acted on by a ____________________.


43.

A rocket blasting off is best represented by Newton’s ____________________
law of motion.


44.

To calculate ____________________ you divide distance traveled by the time it
takes to travel that distance.


45.

A(n) ____________________ is a sloped surface, sometimes called a ramp, that
allows you to lift a heavy load by using less force over a greater distance.

Short Answer


46.

Why does work in fail to equal work out for a real machine?


47.

What is the purpose of a machine?


48.

Can an object’s acceleration be a negative number? Why or why not?


49.

Why would using an inclined plane help you move an object?


50.

If forces occur in equal but opposite pairs, how can anything ever move?


51.

Two crates, one heavy and one light, are at rest on a waxed floor. Which crate
will need a greater force to provide the same acceleration? Use the concept of inertia to explain
your answer.


52.

List the forces that act on a tennis ball during a game and explain how each
force affects the tennis ball.


53.

All objects should fall at the same rate. But a feather falls at a slower rate
than a marble. Explain why this is so.


54.

Explain the role of friction in walking on a sidewalk versus walking on a
sidewalk covered with ice.


55.

You sit on a rock. Your weight is a force acting on the rock. What force acts on
you?


56.

Use Newton's second law to explain why a space shuttle remains in
orbit.


57.

In what two ways can machines make work easier?


58.

How is acceleration related to change in speed?

Problem


59.

A swimmer swims 20 m in 40 s. What is the swimmer’s average speed?


60.

A person is traveling at 20 m/s in a car when the car hits a tree. The person
comes to a complete stop in 0.4 seconds. What was the person’s acceleration?
