Forces Unit Assessment

Take our forces unit assessment quizzes with links back to lessons for support. This unit includes Newton's Laws of Motion and Various Forces. The Pictures to the right and the title link to that sections review lesson.

1: Newtons First Law: Inertia

Newton's First Law Quiz

1 / 4

Which of Newton's Laws describes an objects resistance to a change in motion or rest?

Newton's First Law

Newton's Second Law

Newton's Third Law

Newtons First Law: Law of inertia

This is about a resistance to change in motion. An object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force.

2 / 4

Which statement is related to an objects inertia?

A cup sitting on a car slides off when you hit the breaks

A cup sitting on a windshield slides off because the surface is angled

A cup sitting on a car moves when you grab it

A cup is moving with the car and when you hit the breaks its inertia wants it to keep on going forward. Therefore the cup slides off because it wants to keep its state of motion.

3 / 4

How much force is required to keep an object in motion?

0 N

It's Weight

Depends on its mass

Newtons first law states an object in motion will stay in motion and an object at rest will stay at rest. No force is needed. Think of an asteroid in space

4 / 4

Which has more inertia?

0.34 kg ball

40 kg calf

80 kg boy

Mass is directly related to inertia. The more the mass the more the inertia

Your score is

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2: Newton's Second Law: Net Force Causes Acceleration

Newton's Second Law Quiz

1 / 10

Which of Newton's Laws is most related to a larger object resisting a change of motion more than a less massive one?

First

Second

Third

Newtons First Law: Law of Inertia. An object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force. (More mass more inertia or resistance to change)

Newtons Second Law: Force causes acceleration (F=ma)

Newtons Third Law: All forces are paired, equal and opposite. When you push on an object with 15 Newtons of force it pushes back on you with 15 Newtons of force.

2 / 10

Which of Newton's Laws is most related to all the forces on an object causing the object to accelerate?

First

Second

Third

Newtons First Law: Law of Inertia. An object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force. (More mass more inertia or resistance to change)

Newtons Second Law: Force causes acceleration (F=ma)

Newtons Third Law: All forces are paired, equal and opposite. When you push on an object with 15 Newtons of force it pushes back on you with 15 Newtons of force.

3 / 10

Force and acceleration are ______________ related

directly

inversely

4 / 10

Acceleration and mass are ______________ related

directly

inversely

5 / 10

What is the mass of an object that accelerates at 4 m/s when 20 N of net force is applied?

5 kg

80 kg

0.2 kg

2.0 kg

6 / 10

What is the net force in the picture above

7 N right

22 N right

8 N left

52 N left

30 left is -30
15 right is +15
7 right is +7

Add them together and turn the sign back into a direction (-30 + 15 + 7 = -8)

8 Newtons Left

7 / 10

What is the acceleration on a 5 kg object that has a force of 20 N applied to the right and 5 newtons applied to the left?

5 m/s/s right

3 m/s/s left

5 m/s/s left

3 m/s/s right

8 / 10

What is the net force on a 5 kg object that has a force of 20 N applied to the right and 5 newtons applied to the left?

25 N right

15 N left

25 N left

15 N right

9 / 10

Net force causes _____________________. Pick the best answer

motion in the same direction

acceleration in the same direction

motion in the opposite direction

acceleration in the opposite direction

Net force causes an object to accelerate... not just move. Acceleration always occurs in the same direction as net force. If you are pushing something to the right with a greater force than friction, and its net force is to the right, it will accelerate to the right.

10 / 10

Which direction does an object accelerate?

Always directed up

Always directed down

Always directed the direction of the net force

Acceleration is always in the direction of the net force. If you push a box to the right, with an overall or net force to the right, the object will accelerate to the right.

Your score is

3: Mass and Weight

Mass and Weight Quiz

1 / 6

Joe has a mass of 54 kg. What is his mass on the moon where the acceleration due to gravity is 1.62 m/s²?

54 kg

5.51 kg

87.5 kg

539 kg

Mass does not change. Weight does depending on the acceleration due to gravity.

2 / 6

Joe has a mass of 54 kg. What is his weight on the moon where the acceleration due to gravity is 1.62 m/s²?

5.51 N

539 N

87.5 N

54 N

F_w = mg

m = 54 kg

g = 1.62 m/s²

F_w = (54)(1.62) = 87.48 N

3 / 6

Joe has a mass of 54 kg. What is his weight on the earth?

54 N

87.5 N

529 N

5.51 N

F_w = mg

m = 54 kg

g = 9.8 m/s²

F_w = (54)(9.8) = 529.2 N

4 / 6

Which changes depending on your location?

mass

weight

Mass (kg) never changes because it is a measure of the matter that you are composed of. You are the same matter on earth or on the moon.

Weight (F_w) changes when g changes. g changes depending on your altitude on earth, in space, or on another planet (it is not always 9.8 m/s²which is why many classes use a more rounded 10 m/s²instead.

(F_w = mg)

5 / 6

Which is the term for the molecules that make up an object.

weight

mass

Matter is composed of the atoms/molecules that make up an object

6 / 6

What would happen to your weight if you were on a planet with twice the acceleration due to gravity?

It would quadruple

It would double

It would stay the same

It would half

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4: Newton's Third Law: Action Reaction Pairs

Newton's Laws and The Third Law of Motion Quiz

1 / 8

Which of Newton's Laws is most related to a larger object resisting a change of motion more than a less massive one?

First

Second

Third

Newtons First Law: Law of Inertia. An object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force. (More mass more inertia or resistance to change)

Newtons Second Law: Force causes acceleration (F=ma)

Newtons Third Law: All forces are paired, equal and opposite. When you push on an object with 15 Newtons of force it pushes back on you with 15 Newtons of force.

2 / 8

Which of Newton's Laws is most related to all the forces on an object causing the object to accelerate?

First

Second

Third

Newtons First Law: Law of Inertia. An object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force. (More mass more inertia or resistance to change)

Newtons Second Law: Force causes acceleration (F=ma)

Newtons Third Law: All forces are paired, equal and opposite. When you push on an object with 15 Newtons of force it pushes back on you with 15 Newtons of force.

3 / 8

Which of Newtons Laws are best represented by this scenario.

If you push on a wall with 50 N of force, the wall pushed on you with 50 N of force

Newton's First Law

Newton's Second Law

Newton's Third Law

Newtons First Law: Law of Inertia. An object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force. (More mass more inertia or resistance to change)

Newtons Second Law: Force causes acceleration (F=ma)

Newtons Third Law: All forces are paired, equal and opposite. When you push on an object with 15 Newtons of force it pushes back on you with 15 Newtons of force.

4 / 8

When you are on earth, which of the following is true?

The earth is more massive and pulls you down more than you pull it up

You pull the earth up less than it pulls you down creating weight

The earths pull on you is equal to the force you pull the earth up

Newtons First Law: Law of Inertia. An object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force. (More mass more inertia or resistance to change)

Newtons Second Law: Force causes acceleration (F=ma)

Newtons Third Law: All forces are paired, equal and opposite. When you push on an object with 15 Newtons of force it pushes back on you with 15 Newtons of force.

5 / 8

When hitting a baseball you apply 150 N of force with the bat on the ball. How does the magnitude of force the ball applies to the bat compare?

Less than 150 N

More than 150 N

Exactly 150 N

Newtons Third Law: All forces are paired, equal and opposite. When hit a baseball with 15 Newtons of force forward it hits you with 15 Newtons of force backwards. Magnitude means ignore the direction and just look at the number and unit.

6 / 8

95kg Joe jumps off a 0.8kg skateboard and accelerates at 1.5 m/s/s right what is the acceleration of the skateboard?

98 m/s/s right

178 m/s/s left

114 m/s/s left

0.0126 m/s/s left

F = ma

a = F/m

Forces on both are equal but if mass is less (its inversely related to acceleration) the acceleration caused by an equal force is more.

7 / 8

When a more massive skater jumps of a less massive skateboard. Which is true of the scenario?

The more massive object has more acceleration

The more massive object has less accelration

Both objects have the same acceleration

8 / 8

When a bug hits your windshield. Which of the following are true?

The bug applies an equal of force to your windshield as your windshield to the bug

The windshield applies more force to the bug than the bug to the windshield

The bug applies more force to the windshield than the windshield to the bug

Newtons Third Law: All forces are paired, equal and opposite. When you push on an object with 15 Newtons of force it pushes back on you with 15 Newtons of force. The forces are equal.

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5: Forces: Friction

Friction Quiz

1 / 7

What type of friction do you have while an object is at rest?

Static

Kinetic

Rolling

Static Friction: at rest

Kinetic Friction: moving and can be sliding or rolling which would have a lower coefficient of friction than sliding.

2 / 7

What is the magnitude of frictional force when 162 N of force is required to keep an object in constant motion?

0 n

10 N

16.2 N

162 N

What is the magnitude of frictional force when 162 N of force is required to keep an object in constant motion?

If there is constant motion there is no acceleration and the net force is zero. The frictional force must equal the force applied in the opposite direction so 162 N as well

3 / 7

What is the magnitude of net force when 162 N of force is required to keep an object in constant motion?

0 n

10 N

16.2 N

162 N

Constant motion means no acceleration. Net force (sum of overall forces on an object) must be zero if there is no acceleration.

4 / 7

Which is almost always greater

kinetic friction

static friction

rolling friction

When an object is at rest (static) the surfaces between objects are settled and closer together. With surfaces closer together there is more interaction and therefore more static friction friction than kinetic.

5 / 7

You use a spring scale to measure the amount of force required to first start an object moving. You would use this value to determine the coefficient of ___________ friction.

static

kinetic

Coefficient of static friction. The moment the object first starts moving is also almost equivalent to the maximum force provided by friction while the object was at rest or static.

Force applied equals the magnitude of force of friction in constant motion. If you find the force of friction (F_f), you know the Force applied (F_A)

6 / 7

What is the force required to keep a 0.5 kg brick in constant motion on a wood surface?

0 N

0.45 N

2.2 N

2.9 N

10.9 N

7 / 7

What is the minimum force required to start a 0.5 kg brick moving on a wood surface?

0 N

0.45 N

2.2 N

2.9 N

10.9 N

Your score is

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6: Forces: Air Resistance

Air Resistance and Terminal Velocity Quiz

1 / 8

What is the acceleration of a 1400 N skydiver at terminal velocity?

0 m/s/s

9.8 m/s/s down

9.8 m/s/s up

No net force and no acceleration at terminal velocity

2 / 8

What is the weight of a 1400 N skydiver at terminal velocity?

0 N

1400 N up

1400 N down

The way the question was stated it was giving you weight which is a force (F_w = 1400 N)

3 / 8

What is the air resistance force on a 1400 N skydiver at terminal velocity?

0 N

1400 N up

1400 N down

At terminal velocity net force is zero so air resistance must equal the skydivers weight or 1400 N but directed up

4 / 8

What is net force of a 1400 N skydiver at terminal velocity?

0 N

1400 N up

1400 N down

At terminal velocity a person is no longer accelerating so net force is zero because air resistance force is equal to the weight force

5 / 8

What is the acceleration of a 1400 N skydiver when she encounters 600 N of air resistance? (use g = 9.8 m/s/s)

9.8 m/s/s

0 m/s/s

4.5 m/s/s

5.6 m/s/s

Find Net Force

1400 N weight, which is a vector, directed down and mathematically -1400
600 N air resistance is opposite of motion so up and mathematically is +600
add the vectors together with their signs to get net force
-1400 + 600 = - 800 N or 800 N down

Find Mass

F_w = mg
m =F_w/g
m = 1400/9.8 = 143 kg

Calculate acceleration

F_net= ma

a = F_net/m

a = 800/143 = 5.6 m/s²

6 / 8

What is the mass of a 1400 N skydiver when she encounters 600 N of air resistance? (use g = 9.8 m/s/s)

13720 kg

143 kg

61.2 kg

81.6 kg

Find Mass

F_w = mg
m =F_w/g
m = 1400/9.8 = 143 kg

7 / 8

What is the net force when a 1400 N skydiver encounters 600 N of air resistance?

0 N

800 N down

800 N up

2000 N down

2000 N up

What is the net force when a 1400 N skydiver encounters 600 N of air resistance?

1400 N weight which is a vector directed down and mathematically -1400

600 N air resistance is opposite of motion so up and mathematically is +600

add the vectors together with their signs to get net force

-1400 + 600 = - 800 N or 800 N down

8 / 8

What is the acceleration of a 1400 N skydiver that has no air resistance?

0 m/s/s down

9.8 m/s/s down

5 m/s/s down

6.4 m/s/s down

When air resistance on earth is ignored and an object is not too high up, the acceleration due to gravity is 9.8 m/s/s

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7: Tension Force

626

Tension Quiz

1 / 5

How much tension must be in a rope attached above an object if the normal force on a 500 N object is 100 N.

300 N up

200 N up

400 N up

600 N up

2 / 5

Solve for the tension in one of the ropes suspending the object above.

5.4 N

7.35 N

8.5 N

10.3 N

3 / 5

What is the tension in each of two ropes vertically suspending a 45 kg object? (use g = 9.8 m/s/s)

45 kg

441 N

0.218 N

221 N

Tension if a single rope would have the equal magnitude to the weight down. With two ropes both directed up, they are sharing the weight so divide by two.

F_w = mg

F_w = (45)(9.8) = 441 N

441/2 = 220.5 N

4 / 5

What is the tension in a rope suspending a 45 kg object? (use g = 9.8 m/s/s)

45 kg

441 N

0.218 N

221 N

Tension up would have the equal magnitude to the weight down

F_w = mg

F_w = (45)(9.8) = 441 N

5 / 5

What is the tension in a rope when you apply a force of 100 N to pull an object forward in constant motion.

0 N

100 N backward

10 N backward

100 N forward

10 N forward

Your score is

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8: Hooke's Law and Spring Force

519

Hooke's Law and Springs Quiz

1 / 4

What happens to the magnitude of force required to stretch a spring 0.1 m when the spring constant increases?

force must increase

force must decrease

force stays the same

2 / 4

How much force is in a spring that has a spring constant of 4400 N/m that is displaced 0.03 m?

102 N

65 N

321 N

132 N

3 / 4

What is the spring constant of a spring displaced 0.1 meters when 400 N of force is applied?

40 N/m

4000 N/m

384 N/m

10 N/m

4 / 4

What is the displacement of a spring that has a spring constant of 2000 N/m when a force of 500N is applied?

0.25 m

1000000 m

2.5 m

4 m

Your score is

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9: Forces on Incline Planes

Incline Plane Quiz

1 / 13

Which letter above represents weight?

2 / 13

Which letter above represents the parallel force?

3 / 13

Which letter above represents normal force?

4 / 13

Which letter above represents friction?

5 / 13

Which number above is where the incline angle would be placed?

6 / 13

What happens to the normal force as the angle of incline increases?

Increases

Decreases

Larger incline means less force into the hill (equal to the magnitude of normal force) as more of the weight is going into the component downhill instead

7 / 13

What happens to the downhill force as the angle of incline increases?

Increases

Decreases

Larger incline means more force downhill

8 / 13

What happens to the frictional force as the angle of incline increases?

Increases

Decreases

9 / 13

What is the weight of a 4.0 kg object on a 25° frictionless Incline Plane? (Use g = 9.8 m/s²)

0.41 N

4.0 N

9.8 N

39.2 N

10 / 13

What is the acceleration of a moving object on a 4.0 kg object on a 25° Incline Plane that has a coefficient of friction with the object of 0.43?

0.325 m/s/s

0.56 m/s/s

4.15 m/s/s

11.5 m/s/s

First find the weight (F_w = mg)
Use the weight to find the parallel force down the hill
Use the weight to find the perpendicular force into the hill (also equal to the magnitude of normal force which will be used in the friction equation)
Use the normal force from the step above to figure out the force of friction (F_f = µF_n)
Find the net force (by finding the sum of the forces) subtracting friction uphill from the parallel force downhill
Use the net force in the equation (F_net=ma) to determine the acceleration

11 / 13

What is the Normal force on a 4.0 kg object on a 25° Incline Plane?

0.41 N

4.0 N

16.6 N

35.5 N

12 / 13

What is the downhill force on a 4.0 kg object on a 25° Incline Plane?

0.41 N

4.0 N

16.6 N

35.5 N

13 / 13

What is the frictional force of a moving object on a 4.0 kg object on a 25° frictionless Incline Plane that has a coefficient of friction with the object of 0.43?

12.3 N

15.3 N

16.6 N

35.5 N

Follow through step #5 above on how to determine friction

find the weight
use weight to determine the normal force
use normal force to determine frictional force

Your score is

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