Download Physics

Physics Final Exam
Please do not write on the exam
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1. According to Ohm’s law, resistance is equal to voltage divided by
a. time.
b. conduction.
c. current.
d. potential.
2. In a series circuit with three bulbs, adding another bulb will
a. make the nearest bulb brighter.
b. make some of the bulbs dimmer.
c. make all the bulbs brighter.
d. make all the bulbs dimmer.
3. The charge on a proton is
a. negative, and the charge on an electron is positive.
b. positive, and the charge on an electron is negative.
c. the same as the charge on an electron.
d. can change according to the situation.
4. Kinetic energy increases as
a. mass increases and velocity decreases.
b. mass decreases and velocity increases.
c. both mass and velocity increase.
d. both mass and velocity decrease.
5. What type of conversion is taking place when natural gas is used to heat water?
a. chemical energy into thermal energy
b. thermal energy into mechanical energy
c. mechanical energy into electromagnetic energy
d. electromagnetic energy into chemical energy
6. When you rub your hands together on a cold day, you use friction to convert
a. mechanical energy into thermal energy.
b. thermal energy into nuclear energy.
c. nuclear energy into electrical energy.
d. electrical energy into electromagnetic energy.
7. Which of the following has kinetic energy?
a. a rock poised for a fall
b. an archer’s bow that is drawn back
c. a rolling bowling ball
d. a car waiting at a red light
8. Visible light is an example of
a. chemical energy.
b. electrical energy.
c. electromagnetic energy.
d. nuclear energy.
9. What happens when two forces act in the same direction?
a. They cancel each other out.
b. The stronger one prevails.
c. They add together.
d. Their sum divided by two is the total force.
10. The tendency of an object to resist change in its motion is known as
a. mass.
b. inertia.
c. force.
d. balance.
11. The greater the mass of an object,
a. the easier the object starts moving.
b. the greater its inertia.
c. the more balanced it is.
d. the more space it takes up.
12. One way to increase acceleration is by
a. increasing mass.
b. decreasing mass.
c. decreasing force.
d. increasing both force and mass proportionally.
13. The force that one surface exerts on another when the two rub against each other is called
a. friction.
b. acceleration.
c. inertia.
d. gravity.
14. The law of universal gravitation states that any two objects in the universe, without exception,
a. attract each other.
b. repel each other.
c. combine to provide a balanced force.
d. create friction.
15. Forces can be added together only if they are
a. acting on the same object.
b. balanced forces.
c. unaffected by gravity.
d. substantial.
16. The product of an object’s mass and velocity is called its
a. inertia.
b. momentum.
c. acceleration.
d. force.
17. An object that travels around another object in space is called a(n)
a. projectile.
b. inertia.
c. mass.
d. satellite.
18. In physical science, a push or a pull is called a(n)
a. force.
b. acceleration.
c. inertia.
d. motion.
19. According to Newton’s third law of motion, when a hammer strikes and exerts force on a nail, the nail
a. creates a friction with the hammer.
b. disappears into the wood.
c. exerts an equal force back on the hammer.
d. moves at a constant speed.
20. The SI unit for force is the
a. newton.
b. meter.
c. kilogram.
d. pound.
21. Balanced forces acting on an object
a. always change the object’s motion.
b. sometimes change the object’s motion.
c. never change the object’s motion.
d. are not related to motion.
22. Air pressure exerted equally on an object from different directions is
a. balanced pressure.
b. gravitational pressure.
c. fluid pressure.
d. constant pressure.
23. If an object floats, the volume of displaced water is equal to the volume of
a. the entire object.
b. the portion of the object that is above water.
c. the portion of the object that is submerged.
d. exactly half of the object.
24. The first step in designing or redesigning a product is
a. thinking about ways to solve the problem.
b. deciding what needs you are trying to meet.
c. building a prototype.
d. fully researching the problem.
25. The region around a magnet where the magnetic force is exerted is known as its
a. magnetic pole.
b. lodestone.
c. magnetic field.
d. magnetic domain.
26. Magnetic poles that are unlike
a. attract each other.
b. repel each other.
c. do not interact.
d. point in the same direction.
27. The basic SI unit of length is the
a. meter.
b. foot.
c. inch.
d. mile.
28. You can show the motion of an object on a line graph in which you plot distance against
a. velocity.
b. time.
c. speed.
d. direction.
29. The steepness of a line on a graph is called the
a. rise.
b. run.
c. slope.
d. the vertical axis.
30. The rate at which velocity changes is called
a. instantaneous speed.
b. direction.
c. acceleration.
d. motion.
31. If speed is measured in meters per second and time is measured in seconds, the unit of acceleration is
a. seconds (s).
b. meters per second (m/s).
c. meters per second per second (m/s2).
d. meters (m).
32. On a graph showing distance versus time, a horizontal line represents an object that is
a. moving at a constant speed.
b. increasing its speed.
c. decreasing its speed.
d. not moving at all.
33. The moon accelerates because it is
a. in a vacuum in space.
b. continuously changing direction.
c. a very large sphere.
d. constantly increasing its speed of orbit.
34. If an object moves in the same direction and at a constant speed for 4 hours, which of the following is true?
a. The object’s speed changed during the 4 hours.
b. The object’s velocity did not change.
c. The object accelerated during the 4 hours.
d. The object decelerated during the 4 hours.
35. If you know a car traveled 300 kilometers in 3 hours, you can find its
a. acceleration.
b. direction.
c. average speed.
d. velocity.
36. In an acceleration graph showing speed versus time, a straight line shows the acceleration is
a. decreasing.
b. increasing.
c. changing.
d. constant.
37. What kind of line on a distance-versus-time graph indicates that the object is accelerating?
a. curved
b. horizontal
c. diagonal
d. vertical
38. Kilo- is a prefix that means
a. one thousandth
b. one hundredth
c. one hundred
d. one thousand
39. A car travels 85 km in the first hour of a trip. The car continues to travel for 2 more hours and travels 200 km. What was the
average speed of the car for the trip?
a. 39 km/h
b. 95 km/h
c. 115 km/h
d. 285 km/h
40. A runner rounding a curve on a track at a constant speed is an example of what type of acceleration?
a. changing direction
b. decreasing velocity
c. increasing velocity
d. instantaneous speed
41. How many different forms, or states, does most matter on Earth exist in?
a. one
b. two
c. three
d. fifty
42. The temperature at which a solid changes into a liquid is called
a. the boiling point.
b. the freezing point.
c. the melting point.
d. absolute zero.
43. Which statement is true of gases?
a. The particles that make up gases are packed together in a relatively fixed position.
b. Gases have a definite volume.
c. Gases have a definite shape.
d. Gases expand to fill all the space available.
44. For work to be done on an object,
a. some force need only be exerted on the object.
b. the object must move some distance as a result of a force.
c. the object must move, whether or not a force is exerted on it.
d. the object must not move.
45. Which of these is an example of work being done on an object?
a. holding a heavy piece of wood at a construction site
b. trying to push a car that doesn’t move out of deep snow
c. pushing a child on a swing
d. holding a door shut on a windy day so it doesn’t blow open
46. If you exert a force of 20 newtons to push a desk 10 meters, how much work do you do on the desk?
a. 200 joules
b. 30 joules
c. 10 joules
d. 100 joules
47. Work is measured in
a. meters.
b. pounds.
c. joules.
d. newtons.
48. The mechanical advantage of a machine is the number of times a machine increases
a. the distance an object is moved.
b. the amount of friction.
c. the change in direction.
d. the force exerted on the machine.
49. Which body parts are shaped like wedges?
a. muscles
b. tendons
c. incisors
d. bones in your legs
50. The fixed point that a lever pivots around is called the
a. axle.
b. pulley.
c. gear.
d. fulcrum.
Short Answer
Use the diagram to answer each question.
51. What would happen if you placed the balloon in Diagram B near a wall?
Use the diagram to answer each question.
52. What will happen to bulb 1 in circuit A if the switch is opened?
53. Will removing bulb 1 in circuit B cause bulb 3 to go out? Explain.
Use the diagram to answer each question.
54. Which letter represents the position at which the basketball has the greatest kinetic energy? Explain.
55. Which letter represents the position at which the basketball has the least kinetic energy? Explain.
Use the diagram to answer each question.
56. Describe how the kinetic and potential energies of the pendulum are changing at position B.
Use the diagram to answer each question. (Assume the longer the arrow, the greater the force acting on the object.)
57. In what direction is the net force acting on the 1-kg object?
58. Compare the acceleration of the 1-kg object with that of the 2-kg object.
Use the diagram to answer each question.
59. What is each curved line around magnet A called?
Use the diagram to answer each question.
60. How would you describe Kathy’s motion? What does such motion mean?
61. How far did Kathy jog in the first 4 minutes?
62. Describe Rachel’s motion at 9 minutes.
Use the diagram to answer each question.
63. Why isn’t the temperature increasing for sections A & B of this graph? What is the energy being used to do. Explain.
Use the diagram to answer each question.
64. In what direction is the buoyant force acting on the block in container A?
65. Compare the buoyant force on the block in container B with the weight of the block.
Essay
66. In an amusement park ride, a girl stands with her back against the inside wall of a circular room. The room begins to whirl
around. After the room reaches a constant speed, the floor drops down, but she doesn’t fall. Identify three forces acting on her
and give the direction of each. Explain which forces are balanced forces.
67. A book is sitting on the dashboard of a car that is stopped at a traffic light. As the car starts to move forward, the book slides
backward off the dashboard. Use the term inertia to explain what happened.
68. A skydiver with a mass of 70 kg accelerates to Earth at a rate of 10 m/s 2 due to gravity. What is the force on the skydiver?
Explain how you determined the answer and its units.
69. A bricklayer lifts a stack of bricks onto his shoulder, carries it across a room, and then lifts the bricks onto a ledge above his
head. Explain if work is being done in each of these three situations.
physics
Answer Section
MULTIPLE CHOICE
1. ANS: C
PTS: 1
OBJ: PS.20.4.1 Explain what Ohm’s law is.
BLM: knowledge
DIF:
L1
STA:
REF: p. PS-707
P.8.C.6
2. ANS: D
PTS: 1
DIF: L2
REF: p. PS-710
OBJ: PS.20.4.3 Identify how many paths currents can take in series and parallel circuits.
STA: P.8.C.6
BLM: comprehension
3. ANS: B
PTS: 1
DIF: L1
OBJ: PS.20.1.1 Explain how electric charges interact. STA:
BLM: knowledge
REF: p. PS-683
P.8.B.1
4. ANS: C
PTS: 1
DIF: L2
OBJ: PS.13.1.2 Name and describe the two basic kinds of energy.
STA: P.8.B.3| P.8.C.4
BLM:
comprehension
REF:
p. PS-444
5. ANS: A
PTS: 1
DIF: L2
OBJ: PS.13.3.1 Describe how different forms of energy are related.
STA: P.8.C.3| P.8.C.4| P.8.C.6
BLM: application
REF:
p. PS-455
6. ANS: A
PTS: 1
DIF: L2
OBJ: PS.13.3.3 State the law of conservation of energy.
BLM: comprehension
REF:
STA:
p. PS-458
P.8.C.3| P.8.C.4
7. ANS: C
PTS: 1
DIF: L2
OBJ: PS.13.1.2 Name and describe the two basic kinds of energy.
STA: P.8.B.3| P.8.C.4
BLM:
application
REF:
p. PS-444
8. ANS: C
PTS: 1
DIF: L2
REF: p. PS-451
OBJ: PS.13.2.2 Name some forms of energy associated with the particles that make up objects.
STA: P.8.C.3| P.8.C.4
BLM:
comprehension
9. ANS: C
PTS: 1
DIF: L2
REF: p. PS-335
OBJ: PS.10.1.2 Explain how balanced and unbalanced forces are related to an object’s motion.
STA: P.8.B.1
BLM: comprehension
10. ANS: B
PTS: 1
DIF:
OBJ: PS.10.3.1 State Newton’s first law of motion.
BLM: knowledge
L1
STA:
REF: p. PS-350
P.8.B.1
11. ANS: B
PTS: 1
DIF:
OBJ: PS.10.3.1 State Newton’s first law of motion.
BLM: comprehension
L2
STA:
REF: p. PS-350
P.8.B.1
12. ANS: B
PTS: 1
DIF: L2
REF: p. PS-352
OBJ: PS.10.2.2 Identify the factors that affect the gravitational force between two objects.
STA: P.8.B.3
BLM: comprehension
13. ANS: A
PTS: 1
DIF: L1
REF: p. PS-341
OBJ: PS.10.2.1 Describe friction, and identify factors that determine the friction force between two objects.
STA:
P.8.B.1
BLM: knowledge
14. ANS: A
PTS: 1
DIF: L1
REF: p. PS-344
OBJ: PS.10.2.2 Identify the factors that affect the gravitational force between two objects.
STA: P.8.B.3
BLM: knowledge
15. ANS: A
PTS: 1
OBJ: PS.10.1.1 Describe what a force is.
BLM: comprehension
DIF:
REF:
STA:
p. PS-335
P.8.B.1
16. ANS: B
PTS: 1
DIF: L1
OBJ: PS.10.4.2 Explain how an object’s momentum is determined.
STA: P.8.B.1
BLM: knowledge
REF:
p. PS-356
17. ANS: D
PTS: 1
DIF: L1
OBJ: PS.10.5.2 Describe the forces that keep a satellite in orbit.
STA: P.8.B.1| P.8.B.3
BLM:
knowledge
REF:
p. PS-363
18. ANS: A
PTS: 1
OBJ: PS.10.1.1 Describe what a force is.
BLM: knowledge
L1
REF:
STA:
p. PS-334
P.8.B.1
L2
STA:
REF: p. PS-353
P.8.B.1
20. ANS: A
PTS: 1
DIF: L1
OBJ: PS.9.1.1 Determine when an object is in motion. BLM:
REF: p. PS-335
knowledge
DIF:
19. ANS: C
PTS: 1
DIF:
OBJ: PS.10.4.1 State Newton’s third law of motion.
BLM: application
L2
21. ANS: C
PTS: 1
DIF: L1
REF: p. PS-337
OBJ: PS.10.1.2 Explain how balanced and unbalanced forces are related to an object’s motion.
STA: P.8.B.1
BLM: knowledge
22. ANS: A
PTS: 1
DIF:
OBJ: PS.11.1.2 Explain how fluids exert pressure.
L2
BLM:
23. ANS: C
PTS: 1
DIF: L2
OBJ: PS.11.2.1 Describe the effect of the buoyant force.
REF: p. PS-375
comprehension
REF: p. PS-382
BLM: comprehension
24. ANS: B
PTS: 1
DIF: L2
REF: p. PS-23
OBJ: PS.1.4.1 Identify the steps in the technology design process, and describe what is involved in each step.
BLM: comprehension
25. ANS: C
PTS: 1
DIF: L2
OBJ: PS.19.1.3 Describe the shape of a magnetic field.
REF: p. PS-657
BLM: comprehension
26. ANS: A
PTS: 1
DIF: L1
OBJ: PS.19.1.2 Explain how magnetic poles interact. STA:
BLM: knowledge
REF: p. PS-656
P.8.B.1
27. ANS: A
PTS: 1
DIF: L1
OBJ: PS.9.1.2 Determine when an object is in motion. BLM:
REF: p. PS-311
knowledge
28. ANS: B
PTS: 1
DIF:
OBJ: PS.9.2.2 Demonstrate how to graph motion.
BLM: knowledge
REF:
STA:
L1
p. PS-316
N.8.A.1
29. ANS: A
PTS: 1
DIF:
OBJ: PS.9.2.2 Demonstrate how to graph motion.
BLM: knowledge
REF:
STA:
p. PS-316
N.8.A.1
30. ANS: C
PTS: 1
DIF: L1
OBJ: PS.9.3.1 Describe the motion of an object as it accelerates.
STA: P.8.B.1
BLM: knowledge
REF:
p. PS-320
31. ANS: C
PTS: 1
OBJ: PS.9.3.2 Calculate acceleration.
L2
P.8.B.1
REF: p. PS-322
BLM: comprehension
L2
REF:
STA:
p. PS-317
N.8.A.1
33. ANS: B
PTS: 1
DIF: L2
OBJ: PS.9.3.1 Describe the motion of an object as it accelerates.
STA: P.8.B.1
BLM: application
REF:
p. PS-321
34. ANS: B
PTS: 1
DIF: L2
OBJ: PS.9.2.1 Calculate an object's speed and velocity.
REF: p. PS-314
BLM: application
35. ANS: C
PTS: 1
DIF: L2
OBJ: PS.9.2.1 Calculate an object's speed and velocity.
REF: p. PS-313
BLM: application
DIF:
STA:
32. ANS: D
PTS: 1
DIF:
OBJ: PS.9.2.2 Demonstrate how to graph motion.
BLM: application
L1
36. ANS: D
PTS: 1
DIF: L2
REF: p. PS-324
OBJ: PS.9.3.3 Describe what graphs are used to analyze the motion of an accelerating object.
STA: N.8.A.1| P.8.B.1
BLM:
application
37. ANS: A
PTS: 1
DIF: L1
REF: p. PS-325
OBJ: PS.9.3.3 Describe what graphs are used to analyze the motion of an accelerating object.
STA: N.8.A.1| P.8.B.1
BLM:
knowledge
38. ANS: D
PTS: 1
DIF: L1
OBJ: PS.9.1.2 Determine when an object is in motion. BLM:
REF: p. PS-311
knowledge
39. ANS: B
PTS: 1
DIF: L3
OBJ: PS.9.2.1 Calculate an object's speed and velocity.
REF: p. PS-313
BLM: application
40. ANS: A
PTS: 1
DIF: L2
OBJ: PS.9.3.1 Describe the motion of an object as it accelerates.
STA: P.8.B.1
BLM: application
REF:
p. PS-321
41. ANS: C
PTS: 1
DIF:
OBJ: PS.14.3.1 Name the three states of matter.
BLM: knowledge
REF:
STA:
p. PS-487
P.8.A.1
L1
42. ANS: C
PTS: 1
DIF: L1
OBJ: PS.14.3.2 Identify the cause of changes of state. STA:
BLM: knowledge
REF: p. PS-488
P.8.A.1| P.8.C.5
43. ANS: D
PTS: 1
DIF:
OBJ: PS.14.3.1 Name the three states of matter.
BLM: comprehension
REF:
STA:
L2
p. PS-487
P.8.A.1
44. ANS: B
PTS: 1
DIF: L1
OBJ: PS.12.1.1 Identify when work is done on an object.
BLM: knowledge
REF:
STA:
p. PS-406
P.8.B.1
45. ANS: C
PTS: 1
DIF: L2
OBJ: PS.12.1.1 Identify when work is done on an object.
BLM: application
REF:
STA:
p. PS-406
P.8.B.1
46. ANS: A
PTS: 1
DIF: L2
OBJ: PS.12.1.2 Calculate the work done on an object. STA:
BLM: application
REF: p. PS-408
P.8.B.1
47. ANS: C
PTS: 1
DIF: L2
OBJ: PS.12.1.2 Calculate the work done on an object. STA:
BLM: comprehension
REF: p. PS-409
P.8.B.1
48. ANS: D
PTS: 1
DIF: L1
OBJ: PS.12.2.2 Calculate the mechanical advantage of a machine.
STA: P.8.B.1
BLM: knowledge
REF:
p. PS-416
49. ANS: C
PTS: 1
DIF: L2
REF:
OBJ: PS.12.3.1 Describe the six kinds of simple machines and their uses.
BLM: comprehension
p. PS-432
50. ANS: D
PTS: 1
DIF: L1
REF:
OBJ: PS.12.3.1 Describe the six kinds of simple machines and their uses.
BLM: knowledge
p. PS-426
SHORT ANSWER
51. ANS:
The balloon would cling to the wall for a short time. The negatively charged balloon will induce a positive charge on the wall.
The positively charged wall and negatively charged balloon will then be attracted to each other because unlike charges attract.
PTS:
OBJ:
STA:
1
DIF: L3
REF: p. PS-685
PS.20.1.3 Describe how static electricity builds up and transfers.
P.8.C.6
BLM: synthesis
52. ANS:
Bulb 1 will go out.
PTS:
OBJ:
STA:
1
DIF: L2
REF: p. PS-709
PS.20.4.3 Identify how many paths currents can take in series and parallel circuits.
P.8.C.6
BLM: analysis
53. ANS:
No; because the three bulbs in circuit B are in parallel, removing bulb 1 will still allow current through bulbs 2 and 3.
PTS:
OBJ:
STA:
1
DIF: L2
REF: p. PS-711
PS.20.4.3 Identify how many paths currents can take in series and parallel circuits.
P.8.C.6
BLM: analysis
54. ANS:
E. As the ball falls from C to E, potential energy is converted to kinetic energy. The velocity of the ball increases as it falls,
which means that the ball attains its greatest velocity, and thus its greatest kinetic energy, at E.
PTS:
OBJ:
STA:
1
DIF: L2
REF: p. PS-444
PS.13.1.2 Name and describe the two basic kinds of energy.
P.8.B.3| P.8.C.4
BLM:
analysis
55. ANS:
C. Kinetic energy depends on the speed of the ball. As the ball rises from A to C, it slows down until the point at which it
changes direction and begins to fall.
PTS: 1
DIF: L2
REF: p. PS-456 | p. PS-457
OBJ: PS.13.3.2 Name common energy transformations.
STA:
BLM: analysis
P.8.C.3| P.8.C.4
56. ANS:
The kinetic energy of the pendulum is increasing and the potential energy is decreasing. Potential energy is being converted to
kinetic energy.
PTS: 1
DIF: L2
REF: p. PS-456
OBJ: PS.13.3.2 Name common energy transformations.
BLM: application
STA:
P.8.C.3| P.8.C.4
57. ANS:
to the left
PTS:
OBJ:
STA:
1
DIF: L2
REF: p. PS-335
PS.10.1.2 Explain how balanced and unbalanced forces are related to an object’s motion.
P.8.B.1
BLM: analysis
58. ANS:
The acceleration of the 1-kg object is twice the acceleration of the 2-kg object.
PTS: 1
DIF: L2
REF: p. PS-352
OBJ: PS.10.3.2 State Newton’s second law of motion. STA:
BLM: analysis
P.8.B.1
59. ANS:
a magnetic field line
PTS:
OBJ:
1
DIF: L2
REF: p. PS-657
PS.19.1.3 Describe the shape of a magnetic field.
BLM: analysis
60. ANS:
Kathy is jogging at a constant speed. Her speed does not change as she moves.
PTS: 1
DIF: L2
REF:
OBJ: PS.9.2.2 Demonstrate how to graph motion.
BLM: analysis
p. PS-316
STA:
N.8.A.1
STA:
N.8.A.1
61. ANS:
600 m
PTS: 1
DIF: L2
REF:
OBJ: PS.9.2.2 Demonstrate how to graph motion.
BLM: analysis
62. ANS:
Rachel is not moving; she is at rest.
p. PS-316
PTS: 1
DIF: L2
REF:
OBJ: PS.9.2.2 Demonstrate how to graph motion.
BLM: analysis
p. PS-317
STA:
N.8.A.1
63. ANS:
The energy is going to change the state of matter from solid to liquid (A) and liquid to gas (B).
PTS: 1
DIF: L2
REF: p. PS-488
OBJ: PS.14.3.2 Identify the cause of changes of state. STA:
BLM: analysis
P.8.A.1| P.8.C.5
64. ANS:
The buoyant force is acting upward on the block of wood.
PTS:
OBJ:
1
DIF: L2
REF: p. PS-381
PS.11.2.1 Describe the effect of the buoyant force.
BLM: analysis
65. ANS:
The buoyant force is less than the weight of the block. The buoyant force acts in an upward direction and the weight of the
block acts in a downward direction. Because the weight is greater than the buoyant force, the block sinks.
PTS:
OBJ:
1
DIF: L2
REF: p. PS-382
PS.11.2.1 Describe the effect of the buoyant force.
BLM: analysis
ESSAY
66. ANS:
The three forces are centripetal force (inward), gravity (downward), and friction (upward). Because the girl does not move up
or down, the forces that act upward and downward on her must be balanced. These two forces are friction and weight.
PTS:
OBJ:
STA:
1
DIF: L3
REF: p. PS-337
PS.10.1.2 Explain how balanced and unbalanced forces are related to an object’s motion.
P.8.B.1
BLM: synthesis
67. ANS:
When the car was stopped at the traffic light, the dashboard (which is part of the car) and the book were both at rest. As the car
accelerated forward, the dashboard moved forward. But no force was exerted directly on the book, so it remained at rest.
Because of its inertia, the book did not move forward when the dashboard moved forward. From the reference point of the car,
the book appeared to move backward, and fell off the dashboard.
PTS: 1
DIF: L3
REF:
OBJ: PS.10.3.1 State Newton’s first law of motion.
BLM: synthesis
p. PS-350
STA:
P.8.B.1
68. ANS:
Force = Mass  Acceleration = 70 kg  10 m/s2 = 700 kg  m/s2 = 700 N
According to Newton’s second law of motion, force equals mass times acceleration. Therefore, if you know both mass and
acceleration, you can find the force. In this case, the mass of the person and the acceleration due to gravity were known. Since
1 N = 1 kg  m/s2, the final unit is the newton.
PTS: 1
DIF: L3
REF: p. PS-351
OBJ: PS.10.3.2 State Newton’s second law of motion. STA:
BLM: analysis
69. ANS:
P.8.B.1
Work is being done when the bricklayer lifts the stack of bricks to his shoulder and again when he raises the stack to the ledge.
In both situations the bricklayer’s force on the stack and the motion of the stack are in the same direction. When the bricklayer
carries the stack, no work is being done because his force on the stack (vertical) and the motion of the stack (horizontal) are
not in the same direction.
PTS: 1
DIF: L3
REF: p. PS-406 | p. PS-407
OBJ: PS.12.1.1 Identify when work is done on an object.
STA:
BLM: synthesis
P.8.B.1