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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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