Newton's Laws
Friction
Calculations
Force Diagrams
Misc.
100

Which of Newton's Laws says "An object at rest will stay at rest until acted on by an outside force?"

Newton's 1st Law

100

What type of friction acts on an object that is in motion?

Sliding Friction Or Kinetic Friction

100

What is the weight of a 12 kg mass?

120 N

FW = mg = 12(10) = 120 N

100

Name BOTH of the unlabeled forces on the force diagram below. 

Upwards force = Normal Force

Downward force = Weight or Gravitational Force

100

If an object is moved from the surface of Earth to the moon, does its mass, inertia, or weight change? 

Weight only

200

Which of Newton's Laws says that if you punch the wall, your hand will hurt because it hits you with the same amount of force?

Newton's 3rd Law

200

Which scenario would have the smallest coefficient of friction?

a) Metal on Ice

b) Wood on Carpet

c) Rubber on Wood

d) Wood on Sandpaper

Metal on Ice

200

A 90 kg model rocket experiences a force of 2000 N during takeoff. What is the Net Force acting on the rocket?

1100 N

Fw = mg = 90 (10) = 900 N

FNet = FA-Fw = 2000 - 900 = 1100 N

200

Assume the box below is moving to the right. Is it moving at a constant velocity, getting faster, or getting slower? 

 Getting Faster

200

Which object has the greatest inertia?

Object Z because inertia and mass are the same thing.

300

Which of Newton's Laws says that if a constant force is applied to an object, but the object's mass increases, then its acceleration will decrease?

Newton's 2nd Law

300

As the Normal Force acting on an object increases, what happens to the amount of friction that object will experience?

The friction will increase. 

300

A 20 kg box is at rest on a floor which has a coefficient of static friction of 0.5 and a coefficient of sliding friction of 0.3 . How much force is required to make the box start moving?

100 N

FN = FW = mg = 20(10) = 200 N

Ff = (coeff of static friction)*FN = 0.5 * 200 = 100 N

300

A tennis ball is thrown at and hits a bowling ball in space (no gravity). A student draws the following force diagram for the two objects. According to Newton's 3rd Law, what is wrong with this force diagram?

The two forces should be equal to each other, so the arrows should be the same length. 

300

If an object is in Equilibrium, what are the two types of motion it could have?

At rest or constant velocity

400

How much Net Force is acting on this object? Which Law does your answer correspond to?

Net Force = 0

Newton's First Law

400

Why is it harder to make an object start moving than it is to keep it moving? Be sure your answer mentions static and sliding friction. 

The maximum static friction (force required to make something start moving) is always greater than the sliding friction (force required to keep it moving).
400

A 90 kg model rocket experiences a force of 2000 N during takeoff. What is the rocket's acceleration during takeoff?

12.2 m/s2

Fw = mg = 90 (10) = 900 N

FNet = FA-Fw = 2000 - 900 = 1100 N

a = FNet/m = 1100/90 = 12.2 m/s2

400

Write the name of each type of force described below.

1. Force that opposes motion

2. Force of gravity acting on an object

3. Force that is exerted by a solid surface and is perpendicular to that surface.

4. The vector sum of all Forces

5. Force in a rope, chain, or cable

1. Friction

2. Weight

3. Normal Force

4. Net Force

5. Tension (Force)

400

Write the units for each of the quantities below:

1. Mass

2. Force

3. Acceleration 

4. Velocity

1. kilograms (kg)

2. Newtons (N)

3. meters per second squared (m/s2)

4. meters per second (m/s)

500

Two people on roller skates push each other. Compare the amount of force AND acceleration each skater experiences. 

They experience equal forces.

The girl experiences a greater acceleration.

500

If an object is on a ramp and the ramp is tilted so it becomes steeper, what would happen to the amount of frictional force acting on the object?

It would decrease because the normal force decreases as a ramp becomes more inclined. 

500

A 20 kg box is at rest on a floor which has a coefficient of static friction of 0.5 and a coefficient of sliding friction of 0.3 . If the box is pushed just enough to set it in motion and that force is maintained, what will its acceleration be?

2 m/s2

FA = 0.5(200) = 100 N

Ff = 0.3 (200) = 60 N

FNet = FA - Ff = 40 N

a = FNet / m = 40/20 = 2 m/s2

500

Draw a force diagram for an object sitting on a rough inclined surface.


500

What is the physics equation for this graph?

 y = mx --> v = a t (velocity = acceleration * time)

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