True/False
Indicate whether the
statement is true or false.
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1.
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A speed that does not vary is called average speed.
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2.
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Acceleration is defined as the rate of change of position.
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3.
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The combination of all forces acting on an object is the net force.
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4.
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Velocity changes when the direction of motion changes.
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5.
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The more mass an object has, the greater its inertia is.
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6.
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Work equals force times distance (W = F ´ d).
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7.
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Newton's third law says that an object in motion is slowed down by
gravity.
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8.
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Friction always acts in a direction opposite of motion.
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9.
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When you walk, you push on the sidewalk, and the sidewalk pushes on you with
equal force.
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10.
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The relationship of force and acceleration of an object is explained using
Newton’s first law of motion.
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Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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11.
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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 |
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12.
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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 |
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13.
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Which describes how velocity changes with time?
a. | acceleration | c. | gravity | b. | average speed | d. | inertia |
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14.
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A person in a head-on 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 |
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15.
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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 |
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16.
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What is the term for speed at any instant in time?
a. | instantaneous speed | c. | constant speed | b. | variable speed | d. | average speed |
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17.
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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 |
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18.
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Which one of the following objects has the greatest inertia?
a. | baseball | c. | pencil | b. | bowling ball | d. | toothpick |
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19.
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A force is which one of these?
a. | a push | c. | a push or pull | b. | a pull | d. | none of these |
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20.
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Force is measured in which units?
a. | kilograms | c. | newtons | b. | degrees | d. | m/s2 |
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21.
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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 |
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22.
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____ is done only when an object moves in the direction of the applied
force.
a. | Friction | c. | Effort | b. | Work | d. | Inertia |
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23.
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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 |
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24.
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A(n) ____ is a rod or plank that pivots about a fixed point.
a. | wedge | c. | pulley | b. | axle | d. | lever |
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25.
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According to Newton’s second law of motion, ____.
a. | a = Fnet/m | c. | a =
m/Fnet | b. | a = m X Fnet
X s | d. | a = s
X m |
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Matching
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Match the units with the descriptions below.
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26.
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the unit of force
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27.
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the unit of average speed
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28.
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the unit of work
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29.
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the unit of acceleration
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30.
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the unit of distance
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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 |
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31.
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The harder you pedal a bicycle, the faster it will go.
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32.
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the main reason a person can jump off the ground
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33.
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your front teeth
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34.
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the cord on a window blind
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35.
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A hockey puck will slide across ice for a long time when hit.
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Completion
Complete each
statement.
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36.
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According to Newton’s Third Law, forces always occur in equal but
____________________ pairs.
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37.
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The ____________________ is the combination of all the forces acting on an
object.
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38.
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____________________ measures the quantity of matter in an object.
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39.
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The acceleration of an object can be shown on a(n) ____________________
graph.
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40.
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Machines can change the ____________________ of the force you apply and the
____________________ of the force.
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41.
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The force that resists motion between two objects that are in contact with each
other is ____________________.
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42.
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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 ____________________.
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43.
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A rocket blasting off is best represented by Newton’s ____________________
law of motion.
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44.
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To calculate ____________________ you divide distance traveled by the time it
takes to travel that distance.
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45.
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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.
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Short Answer
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46.
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Why does work in fail to equal work out for a real machine?
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47.
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What is the purpose of a machine?
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48.
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Can an object’s acceleration be a negative number? Why or why not?
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49.
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Why would using an inclined plane help you move an object?
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50.
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If forces occur in equal but opposite pairs, how can anything ever move?
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51.
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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.
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52.
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List the forces that act on a tennis ball during a game and explain how each
force affects the tennis ball.
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53.
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All objects should fall at the same rate. But a feather falls at a slower rate
than a marble. Explain why this is so.
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54.
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Explain the role of friction in walking on a sidewalk versus walking on a
sidewalk covered with ice.
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55.
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You sit on a rock. Your weight is a force acting on the rock. What force acts on
you?
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56.
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Use Newton's second law to explain why a space shuttle remains in
orbit.
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57.
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In what two ways can machines make work easier?
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58.
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How is acceleration related to change in speed?
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Problem
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59.
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A swimmer swims 20 m in 40 s. What is the swimmer’s average speed?
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60.
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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?
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