Download Unit 7 Forces and Motion Study Guide Answer Section

Unit 7 Forces and Motion Study Guide
Multiple Choice
Identify the choice that best completes the statement or answers the question.
Figure 11-1
____
1. Examine Figure 11-1. If you were standing under the tree, which object would appear to be moving?
a. the tree
c. the boy
b. the airplane
d. the building
____
2. A passenger in the rear seat of a car moving at a steady speed is at rest relative to
a. the side of the road.
c. the front seat of the car.
b. a pedestrian on the corner ahead.
d. the wheels of the car.
____
3. One kilometer equals 1000 meters. What does the prefix kilo- mean?
a. 1
c. 100
b. 10
d. 1000
____
4. A person walks 1 mile every day for exercise, leaving her front porch at 9:00 am. and returning to her front
porch at 9:25 am. What is the total displacement of her daily walk?
a. 1 mile
c. 25 minutes
b. 0
d. none of the above
____
5. A person drives north 6 blocks, then turns west, and drives 6 blocks. The driver then turns south and drives 6
blocks. How could the driver have made the distance shorter while maintaining the same displacement?
a. by driving west 6 blocks from the starting point
b. by driving north 4 block and west 7 blocks
c. by driving south 6 blocks from the starting point
d. by driving back to the starting point by the same route
____
6. What is the most appropriate SI unit to express the speed of a cyclist in the last leg of a 10-km race?
a. km/s
c. mm/s
b. km/h
d. cm/h
____
7. Speed is the ratio of the distance an object moves to
a. the amount of time needed to travel the distance.
b. the direction the object moves.
c. the displacement of the object.
d. the motion of the object.
____
8. A car traveled 60 km in 2 hours, 84 km in the next 1 hour, and then 68 km in 2 hours before reaching its
destination. What was the car’s average speed?
a. 212 km/h
c. 148 km/h
b. 42 km/h
d. 1060 km/h
____
9. What is the speed of a bobsled whose distance-time graph indicates that it traveled 100 m in 25 s?
a. 4 m/s
c. 0.25 mph
b. 2500 m/s
d. 100 m/s
____ 10. The rate at which velocity changes is called
a. speed.
b. vectors.
c. acceleration.
d. motion.
____ 11. Suppose you increase your walking speed from 1 m/s to 3 m/s in a period of 1 s. What is your acceleration?
a. 2 m/s2
c. 4 m/s2
2
b. 5 m/s
d. 3 m/s2
____ 12. An object moving at 30 m/s takes 5 s to come to a stop. What is the object’s acceleration?
a. 30 m/s2
c. –6 m/s2
2
b. –30 m/s
d. 6 m/s2
____ 13. A train approaching a crossing changes speed from 25 m/s to 10 m/s in 240 s. How can the train’s
acceleration be described?
a. The train’s acceleration is positive.
b. The train is not accelerating.
c. The train will come to rest in 6 minutes.
d. The train’s acceleration is negative.
____ 14. The SI unit of force is the
a. joule.
b. kilogram.
c. meter.
d. newton.
____ 15. Which of the following relationships is correct?
a. 1 N = 1 kg
c. 1 N = 1 kg·m/s
b. 1 N = 1 kg·m
d. 1 N = 1 kg·m/s2
____ 16. When an unbalanced force acts on an object,
a. the object’s motion does not change.
b. the object accelerates.
c. the weight of the object decreases.
d. the inertia of the object increases.
____ 17. When a pair of balanced forces acts on an object, the net force that results is
a. greater in size than both forces combined.
b. greater in size than one of the forces.
c. equal in size to one of the forces.
d. equal to zero.
____ 18. According to Newton’s second law of motion, the acceleration of an object equals the net force acting on the
object divided by the object’s
a. mass.
c. velocity.
b. momentum.
d. weight.
____ 19. If a force of 12 N is applied to an object with a mass of 2 kg, the object will accelerate at
a. 0.17 m/s2.
c. 6 m/s2.
2
b. 24 m/s .
d. 12 m/s2.
____ 20. Your weight equals your
a. mass.
b. mass divided by the net force acting on you.
c. mass times the acceleration due to gravity.
d. mass times your speed.
____ 21. The acceleration due to gravity on the surface of Mars is about one third the acceleration due to gravity on
Earth’s surface. The weight of a space probe on the surface of Mars is about
a. nine times greater than its weight on Earth’s surface.
b. three times greater than its weight on Earth’s surface.
c. one third its weight on Earth’s surface.
d. the same as its weight on Earth’s surface.
____ 22. Newton’s third law of motion describes
a. action and reaction forces.
b. balanced forces.
c. centripetal forces.
d. net force.
____ 23. In which of the following are action and reaction forces involved?
a. when a tennis racket strikes a tennis ball
b. when stepping from a curb
c. when rowing a boat
d. all of the above
____ 24. As an astronaut travels far away from Earth, her weight
a. decreases because gravity decreases.
b. decreases because her mass decreases.
c. increases because gravity increases.
d. remains the same because her mass remains the same.
Completion
Complete each statement.
25. The SI unit for measuring ____________________ is the meter.
26. The sum of two or more vectors is called the _________________________.
27. Speed is measured in units of _________________________.
28. A car’s speedometer measures _________________________.
29.
is the equation that defines _________________________.
30. The difference between speed and velocity is that velocity indicates the ____________________ of motion
and speed does not.
31. A distance-time graph indicates an object moves 20 km in 4 h. The average speed of the object is
____________________ km/h.
32. A moving object does not ____________________ if its velocity remains constant.
33. Freely falling objects accelerate at 9.8 m/s2 because the force of ____________________ acts on them.
34. The velocity of an object moving in a straight line changes at a constant rate when the object is experiencing
constant ____________________.
35. The acceleration of a moving object is calculated by dividing the change in ____________________ by the
time over which the change occurs.
36. A push or pull is an example of a(an) ____________________.
37. The acceleration of an object is equal to the net ____________________ acting on the object divided by the
object’s ____________________.
38. The force of gravity acting on an object is the object’s ____________________.
39. When you push on a wall, the ____________________ pushes back on you.
40. The universal force that is effective over the longest distances is ____________________.
Unit 7 Forces and Motion Study Guide
Answer Section
MULTIPLE CHOICE
1. ANS: B
OBJ: 11.1.1
STA: SPS3.b
2. ANS: C
OBJ: 11.1.1
STA: SPS3.b
3. ANS: D
OBJ: 11.1.2
4. ANS: B
OBJ: 11.1.3
5. ANS: A
OBJ: 11.1.3
6. ANS: B
OBJ: 11.2.1
7. ANS: A
OBJ: 11.2.1
8. ANS: B
OBJ: 11.2.2
9. ANS: A
OBJ: 11.2.4
10. ANS: C
OBJ: 11.3.1
STA: SPS8.a
11. ANS: A
OBJ: 11.3.3
12. ANS: C
OBJ: 11.3.3
13. ANS: D
OBJ: 11.3.5
14. ANS: D
OBJ: 12.1.1
15. ANS: D
OBJ: 12.1.1
16. ANS: B
OBJ: 12.1.2
it.
17. ANS: D
OBJ: 12.1.2
it.
18. ANS: A
OBJ: 12.2.2
values. STA:
PTS: 1
DIF: L1
Identify frames of reference and describe how they are used to measure motion.
PTS: 1
DIF: L2
Identify frames of reference and describe how they are used to measure motion.
PTS: 1
DIF: L1
Identify appropriate SI units for measuring distances.
PTS: 1
DIF: L1
Distinguish between distance and displacement.
PTS: 1
DIF: L2
Distinguish between distance and displacement.
PTS: 1
DIF: L1
Identify appropriate SI units for measuring speed.
PTS: 1
DIF: L2
Identify appropriate SI units for measuring speed.
PTS: 1
DIF: L2
Compare and contrast average speed and instantaneous speed.
PTS: 1
DIF: L1
Calculate the speed of the object using slopes.
STA: SCSh3.d
PTS: 1
DIF: L1
Identify changes in motion that produce acceleration.
PTS: 1
DIF: L1
Calculate the acceleration of an object.
STA: SPS8.a
PTS: 1
DIF: L2
Calculate the acceleration of an object.
STA: SPS8.a
PTS: 1
DIF: L2
Classify acceleration as positive or negative.
STA: SCSh3.d
PTS: 1
DIF: L1
Describe examples of force and identify appropriate SI units used to measure force.
PTS: 1
DIF: L2
Describe examples of force and identify appropriate SI units used to measure force.
PTS: 1
DIF: L1
Explain how the motion of an object is affected when balanced and unbalanced forces act on
PTS: 1
DIF: L2
Explain how the motion of an object is affected when balanced and unbalanced forces act on
PTS: 1
DIF: L1
Describe Newton’s second law of motion and use it to calculate acceleration, force, and mass
SPS8.b.1
19. ANS: C
OBJ: 12.2.2
values. STA:
20. ANS: C
OBJ: 12.2.3
21. ANS: C
OBJ: 12.2.3
22. ANS: A
OBJ: 12.3.1
STA: SPS8.d
23. ANS: D
OBJ: 12.3.1
STA: SPS8.d
24. ANS: A
OBJ: 12.4.3
force. STA:
PTS: 1
DIF: L2
Describe Newton’s second law of motion and use it to calculate acceleration, force, and mass
SPS8.b.1
PTS: 1
DIF: L1
Relate the mass of an object to its weight.
STA: SPS8.b.2
PTS: 1
DIF: L2
Relate the mass of an object to its weight.
STA: SPS8.b.2
PTS: 1
DIF: L1
Explain how action and reaction forces are related according to Newton’s third law of motion.
PTS: 1
DIF: L2
Explain how action and reaction forces are related according to Newton’s third law of motion.
PTS: 1
DIF: L1
Define Newton’s law of universal gravitation and describe the factors affecting gravitational
SPS8.
COMPLETION
25. ANS:
distance or
length
PTS: 1
DIF: L1
OBJ: 11.1.2 Identify appropriate SI units for measuring distances.
26. ANS: resultant vector
PTS: 1
DIF: L1
STA: SPS8.
27. ANS: meters per second
OBJ: 11.1.4 Calculate displacement using vector addition.
PTS: 1
DIF: L1
28. ANS: instantaneous speed
OBJ: 11.2.1 Identify appropriate SI units for measuring speed.
PTS: 1
DIF: L1
OBJ: 11.2.2 Compare and contrast average speed and instantaneous speed.
29. ANS: average speed
PTS: 1
DIF: L2
OBJ: 11.2.2 Compare and contrast average speed and instantaneous speed.
30. ANS: direction
PTS: 1
STA: SPS8.
31. ANS: 5
DIF: L1
OBJ: 11.2.3 Interpret distance-time graphs.
PTS: 1
STA: SCSh3.d
32. ANS: accelerate
DIF: L2
OBJ: 11.2.4 Calculate the speed of the object using slopes.
PTS:
OBJ:
STA:
33. ANS:
1
DIF: L1
11.3.1 Identify changes in motion that produce acceleration.
SPS8.a
gravity
PTS: 1
DIF: L1
STA: SPS8.a | SPS8.b
34. ANS: acceleration
OBJ: 11.3.2 Describe examples of constant acceleration.
PTS: 1
DIF: L2
STA: SPS8.a | SPS8.b
35. ANS:
speed or
velocity
OBJ: 11.3.2 Describe examples of constant acceleration.
PTS: 1
STA: SPS8.a
36. ANS: force
OBJ: 11.3.3 Calculate the acceleration of an object.
DIF: L1
PTS: 1
DIF: L1
OBJ: 12.1.1 Describe examples of force and identify appropriate SI units used to measure force.
37. ANS: force, mass
PTS: 1
DIF: L1
OBJ: 12.2.2 Describe Newton’s second law of motion and use it to calculate acceleration, force, and mass
values. STA:
SPS8.b.1
38. ANS: weight
PTS: 1
STA: SPS8.b.2
39. ANS: wall
PTS:
OBJ:
STA:
40. ANS:
DIF: L1
OBJ: 12.2.3 Relate the mass of an object to its weight.
1
DIF: L2
12.3.1 Explain how action and reaction forces are related according to Newton’s third law of motion.
SPS8.d
gravity
PTS: 1
DIF: L2
OBJ: 12.4.3 Define Newton’s law of universal gravitation and describe the factors affecting gravitational
force. STA:
SPS8.