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8th Grade
Forces and Motion
Study Guide
www.njctl.org
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1 A snail travels 10 m in 3000 seconds. What is the snail's average speed?
A 60000 m/s
B 0.02 m/s
C 600 m/s
D 0.003 m/s
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1 A snail travels 10 m in 3000 seconds. What is the snail's average speed?
A 60000 m/s
B 0.02 m/s
C 600 m/s
D 0.003 m/s[This object is a pull tab]
Ans
wer D
Slide 3 (Answer) / 40
2 A blimp travels at 3 m/s for 1000 s. What distance does the blimp cover in that time?
A 500 m/s
B 3000 m
C 4500 m/s
D 500 m
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2 A blimp travels at 3 m/s for 1000 s. What distance does the blimp cover in that time?
A 500 m/s
B 3000 m
C 4500 m/s
D 500 m[This object is a pull tab]
Ans
wer B
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3 When your teacher times your mile run at 8.2 minutes, that means your speed was 0.12 mi/min. Was this your average speed or your instantaneous speed?
A Average Speed
B Instantaneous Speed
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3 When your teacher times your mile run at 8.2 minutes, that means your speed was 0.12 mi/min. Was this your average speed or your instantaneous speed?
A Average Speed
B Instantaneous Speed
[This object is a pull tab]
Ans
wer
avg speed =
8.2mi/min
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4 Does a speedometer measure the average speed or the instantaneous speed?
A Average Speed
B Instantaneous Speed
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4 Does a speedometer measure the average speed or the instantaneous speed?
A Average Speed
B Instantaneous Speed
[This object is a pull tab]
Ans
wer Instantaneous
Speed
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5 A swordfish travels for two hours. The first hour he covers 110 kilometers, and the second hour he covers 110 kilometers. What is the average speed of the swordfish?
A 55 km/h
B 84 km/h
C 110 km/h
D 194 km/h
Hint: Remember that average speed is total distance travelled divided by total time
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5 A swordfish travels for two hours. The first hour he covers 110 kilometers, and the second hour he covers 110 kilometers. What is the average speed of the swordfish?
A 55 km/h
B 84 km/h
C 110 km/h
D 194 km/h
Hint: Remember that average speed is total distance travelled divided by total time
[This object is a pull tab]
Ans
wer C
Slide 7 (Answer) / 40
6 A dog walks outside to go the bathroom every day. If she walks outside at a speed of 3 meters per second and walks 150 meters before she uses the bathroom, how long does it take her?
A 50 seconds
B 2 minutes
C 188 seconds
D 90 seconds
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6 A dog walks outside to go the bathroom every day. If she walks outside at a speed of 3 meters per second and walks 150 meters before she uses the bathroom, how long does it take her?
A 50 seconds
B 2 minutes
C 188 seconds
D 90 seconds[This object is a pull tab]
Ans
wer A
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7 Carlos and Gina are riding on their horses to go into town. They travel 140 meters in 14 seconds going west. What is their velocity?
A 490 m/s west
B 10 m/s west
C 490 m/s
D 10 m/s
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7 Carlos and Gina are riding on their horses to go into town. They travel 140 meters in 14 seconds going west. What is their velocity?
A 490 m/s west
B 10 m/s west
C 490 m/s
D 10 m/s[This object is a pull tab]
Ans
wer B
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8 A car travels 200 km/h west for 2 hours. The car then travels 150 km/h east for one hour. What is the car's position relative to its starting position?
A 50 km west
B 150 km west
C 250 km west
D 50 km east
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8 A car travels 200 km/h west for 2 hours. The car then travels 150 km/h east for one hour. What is the car's position relative to its starting position?
A 50 km west
B 150 km west
C 250 km west
D 50 km east
[This object is a pull tab]
Ans
wer C
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9 A nitro-methane powered top fuel dragster launches from rest to race against an opponent. Why did the car accelerate?
A increased speed
B decreased speed
C changed direction
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9 A nitro-methane powered top fuel dragster launches from rest to race against an opponent. Why did the car accelerate?
A increased speed
B decreased speed
C changed direction
[This object is a pull tab]
Ans
wer A
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10 A driver hits the brakes to slow down at an intersection. As the car's speed is decreasing it has
A positive acceleration
B negative acceleration
C no acceleration
D more information is needed
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10 A driver hits the brakes to slow down at an intersection. As the car's speed is decreasing it has
A positive acceleration
B negative acceleration
C no acceleration
D more information is needed
[This object is a pull tab]
Ans
wer B
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11 Which of the following graphs depicts the acceleration of a runner speeding up to pass someone.
A B
C
x
Y
Spe
ed (m
/s)
Time (s)x
Y
Spe
ed (m
/s)
Time (s)
x
Y
Spe
ed (m
/s)
Time (s)
D
x
Y
Spe
ed (m
/s)
Time (s)
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11 Which of the following graphs depicts the acceleration of a runner speeding up to pass someone.
A B
C
x
Y
Spe
ed (m
/s)
Time (s)x
Y
Spe
ed (m
/s)
Time (s)
x
Y
Spe
ed (m
/s)
Time (s)
D
x
Y
Spe
ed (m
/s)
Time (s)[This object is a pull tab]
Ans
wer C
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12 Which of the following speed vs time graphs corresponds to the position vs time graph shown in the graph below?
A
B
C
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12 Which of the following speed vs time graphs corresponds to the position vs time graph shown in the graph below?
A
B
C
[This object is a pull tab]
Ans
wer A
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13 A ball is traveling down a hill at 4 m/s. If the ball increases in speed to 8 m/s in 4 seconds, what is the acceleration of the ball?
A 4 m/sB 4 m/s/sC 1 m/sD 1 m/s/s
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13 A ball is traveling down a hill at 4 m/s. If the ball increases in speed to 8 m/s in 4 seconds, what is the acceleration of the ball?
A 4 m/sB 4 m/s/sC 1 m/sD 1 m/s/s
[This object is a pull tab]
Ans
wer D
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14 Forces are all around us. Which of the following do you think are examples of forces? (choose all that apply)
A Gravity
B Friction
C Muscles
D Wind
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14 Forces are all around us. Which of the following do you think are examples of forces? (choose all that apply)
A Gravity
B Friction
C Muscles
D Wind [This object is a pull tab]
Ans
wer A & B
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15 What is the SI unit for force?
A Pounds
B Kilograms
C Newtons
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15 What is the SI unit for force?
A Pounds
B Kilograms
C Newtons[This object is a pull tab]
Ans
wer C
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16 A +20 N force acts on a car and at the same time, a -30 N force acts on the car. What is the net force acting on the car and is it balanced?
A -30 N unbalanced
B -10 N unbalanced
C -10 N balanced
D + 30 balanced
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16 A +20 N force acts on a car and at the same time, a -30 N force acts on the car. What is the net force acting on the car and is it balanced?
A -30 N unbalanced
B -10 N unbalanced
C -10 N balanced
D + 30 balanced[This object is a pull tab]
Ans
wer B
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17 The force of gravitation between an object and a planet is increased as they move away from each other:
True
False
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17 The force of gravitation between an object and a planet is increased as they move away from each other:
True
False
[This object is a pull tab]
Ans
wer False
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18 A 100 kg kid is on the moon, where g = 1.67 m/s2 . What is the boy's weight?
A 83.5 kg
B 167 kg
C 167 N
D 29.9 N
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18 A 100 kg kid is on the moon, where g = 1.67 m/s2 . What is the boy's weight?
A 83.5 kg
B 167 kg
C 167 N
D 29.9 N[This object is a pull tab]
Ans
wer C
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19 What is the net force acting on the object below?
7 N
-8 N
-10 N
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19 What is the net force acting on the object below?
7 N
-8 N
-10 N
[This object is a pull tab]
Ans
wer -11 N
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20 Is the object in equilibrium?
Yes
No
7 N
-8 N
-10 N
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20 Is the object in equilibrium?
Yes
No
7 N
-8 N
-10 N
[This object is a pull tab]
Ans
wer No
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21 What is the net force acting on the object below?
25 N
-15N
-10 N
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21 What is the net force acting on the object below?
25 N
-15N
-10 N
[This object is a pull tab]
Ans
wer
0 N
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22 Is the object in equilibrium?
Yes
No
25 N
-15N
-10 N
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22 Is the object in equilibrium?
Yes
No
25 N
-15N
-10 N
[This object is a pull tab]
Ans
wer Yes
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23 Acceleration due to gravity on Jupiter is 26.1 m/s2 . How much would a 25 kg person weigh on Jupiter?
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23 Acceleration due to gravity on Jupiter is 26.1 m/s2 . How much would a 25 kg person weigh on Jupiter?
[This object is a pull tab]
Ans
wer 653 N
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24 Acceleration due to gravity on Earth's Moon is 1.67 m/s2 . How much would a 113 kg person weigh on Earth's Moon?
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24 Acceleration due to gravity on Earth's Moon is 1.67 m/s2 . How much would a 113 kg person weigh on Earth's Moon?
[This object is a pull tab]
Ans
wer 189 N
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25 Inertia is the reluctance any material object has to change its state of motion.
True
False
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25 Inertia is the reluctance any material object has to change its state of motion.
True
False[This object is a pull tab]
Ans
wer
True
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26 The law of inertia applies to:
A moving objects
B nonmoving objects
C both moving and nonmoving objects
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26 The law of inertia applies to:
A moving objects
B nonmoving objects
C both moving and nonmoving objects
[This object is a pull tab]
Ans
wer
C
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27 Which object has the greatest inertia?
A Car
B Tennis Ball
C Freight Train
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27 Which object has the greatest inertia?
A Car
B Tennis Ball
C Freight Train [This object is a pull tab]
Ans
wer C
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28 A ball will accelerate and increase its velocity when it feels an unbalanced force.
True
False
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28 A ball will accelerate and increase its velocity when it feels an unbalanced force.
True
False
[This object is a pull tab]
Ans
wer True
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29 When the force acting on an object decreases, the resulting acceleration will:
A remain constant
B increase
C decrease
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29 When the force acting on an object decreases, the resulting acceleration will:
A remain constant
B increase
C decrease[This object is a pull tab]
Ans
wer C
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30 When an object's mass is decreased but the applied force stays the same, the resulting acceleration will:
A remain constant
B increase
C decrease
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30 When an object's mass is decreased but the applied force stays the same, the resulting acceleration will:
A remain constant
B increase
C decrease[This object is a pull tab]
Ans
wer B
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31 You are riding your bicycle to the park to meet a few friends. As you ride, you apply a force of 40 N and accelerate at a rate of 0.4 m/s2 . What is the total mass of the bicycle and you?
A 75 kg
B 100 kg
C 120 kg
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31 You are riding your bicycle to the park to meet a few friends. As you ride, you apply a force of 40 N and accelerate at a rate of 0.4 m/s2 . What is the total mass of the bicycle and you?
A 75 kg
B 100 kg
C 120 kg
[This object is a pull tab]
Ans
wer B
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32 When you sit on a chair, the chair pushes back with force equal to your weight.
True
False
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32 When you sit on a chair, the chair pushes back with force equal to your weight.
True
False
[This object is a pull tab]
Ans
wer True
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33 Which of the following statements pertains to the third law of motion?
A Action and Reaction pairs always act on the same object.
B Mass is indirectly proportional to acceleration.
C An object at rest will remain at rest unless acted on by an unbalanced force.
D If a force occurs, action reaction forces are present.
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33 Which of the following statements pertains to the third law of motion?
A Action and Reaction pairs always act on the same object.
B Mass is indirectly proportional to acceleration.
C An object at rest will remain at rest unless acted on by an unbalanced force.
D If a force occurs, action reaction forces are present.
[This object is a pull tab]
Ans
wer D
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34 How can a small toy have the same momentum as a large car?
A toy has large speed
B both car and toy are at rest
C toy has no mass
D A & B
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34 How can a small toy have the same momentum as a large car?
A toy has large speed
B both car and toy are at rest
C toy has no mass
D A & B [This object is a pull tab]
Ans
wer D
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35 If a 3 kg toy truck is moving at 4 m/s, what is the toy's momentum?
A 3 m/s
B 2 kgm/s
C 12 kgm/s
D 12 m/s
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35 If a 3 kg toy truck is moving at 4 m/s, what is the toy's momentum?
A 3 m/s
B 2 kgm/s
C 12 kgm/s
D 12 m/s [This object is a pull tab]
Ans
wer C
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36 What two factors does momentum depend on?
A mass and volume
B mass and acceleration
C mass and velocity
D mass and force
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36 What two factors does momentum depend on?
A mass and volume
B mass and acceleration
C mass and velocity
D mass and force
[This object is a pull tab]
Ans
wer C
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37 The law of conservation of momentum states that the total momentum after a collision increases from its value before the collision.
True
False
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37 The law of conservation of momentum states that the total momentum after a collision increases from its value before the collision.
True
False
[This object is a pull tab]
Ans
wer False
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38 According to Newton's 3rd law, action reaction pairs are equal and opposite to each other. Why do these paired forces sometimes cause different motions if they are equal?
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38 According to Newton's 3rd law, action reaction pairs are equal and opposite to each other. Why do these paired forces sometimes cause different motions if they are equal?
[This object is a pull tab]
Ans
wer
because they act on different
objects
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