Unit 03 Review: Forces and Newton's Laws

Unit 03 Review

Forces and Newton's Laws

Module 3-1: Weight and Friction

• Mass and Weight are NOT the same! Weight depends on Mass.

• Weight is the downward force of gravity pulling on an object.

• ​Friction is a contact force that resists motion. ​It depends on the surfaces' material and the force pushing them together.

• The coefficient of friction ​determines how "sticky" a surface is.

• Higher = "Grippy" & Lower = "Slippy"

Multiple Choice

What is mass?

• How much MATTER makes up an object.

• How much GRAVITY is pulling an object.

Multiple Choice

If an object mass is 30 Kg on the Earth, what would be it's weight? Assume Earth's gravity acceleration is 10 m/s²

• 30 N

• .3 N

• 300 N

• 30 kg

Multiple Select

Select all that apply.

Mass is...

• the quantity of matter in an object.

• a measure of an object's inertia.

• the same in different locations

• equal to the weight of an object.

Multiple Choice

What would happen to your weight if Earth's mass was cut in half?

• increase because gravitational force increases

• decrease because gravitational force decreases

• decrease because gravitational force increases

• increase because gravitational force decreases

Multiple Choice

Compared to your weight and mass on Earth, if you were on the moon:

• your weight and mass would be less.

• your weight would be less but your mass would remain the same.

• your weight would remain the same, but your mass would be less.

• your weight would be greater, but your mass would remain the same.

Multiple Choice

A force that results from two objects rubbing past each other.

• Gravity

• Friction

• Normal Force

• Acceleration

Multiple Select

What are two factors that determine the amount of friction between objects? Select both.

• Force pressing them together

• Surface roughness

• Mass

• Contact Area

Multiple Choice

Which would NOT be a way of reducing friction?

• Making the surfaces smoother

• Changing from sliding friction to rolling friction

• Using lubricants such as waxes, oils, or grease

• Using kitty litter on snow and ice to help your car gain traction

Poll

How confident do you feel about the material we just reviewed?

• Very confident. I am ready for the assessment!

• I understand most of it, but there are some things I need to study.

• Neutral. I understand some of it, but I need to review quite a bit.

• Overall, I am more confused than confident. I need to review a lot more.

• I am totally lost. I do not understand any of this material.

Module 3-2 and 3-3: Newton's Laws

• 1st: An object will not change its motion unless acted on by an unbalanced force.

• 2nd: The acceleration of an object is directly proportional to the applied force.

• 3rd: When one object exerts a force on another, the second object exerts an equal and opposite force in return.

Multiple Choice

The tendency of an object to resist being moved or if in motion, being stopped is...

• inertia

• friction

• force

• weight

Multiple Choice

The unbalanced force acting on an object equals the object's mass times its acceleration is which law?

• 1st

• 2nd

• 3rd

• None of These

Multiple Choice

As the acceleration of an object increases, what happens to the force of the object?

• Force increases

• Force decreases

• Force stays the same

Multiple Choice

Will it take more force to push an empty shopping cart or a shopping cart that is full?

• Empty Cart

• Full Cart

• They will require equal force.

Multiple Choice

When a heavy football player and a light one run into each other, who exerts more force?

• Light Player

• Heavy Player

• They exert equal forces.

Multiple Choice

A person steps out of the boat and onto the dock.  As the person moves forward onto the dock, the boat moves backward.  Which statement best describes the backward motion of the boat as the person steps forward?

• For every action there is an equal and opposite reaction.

• Every mass exerts a force on every other mass.

• An object at rest tends to stay at rest.

• Friction opposes the motion of an object.

Multiple Choice

According to Newton’s first law of motion, a moving object that is not acted on by an unbalanced force will

• remain in motion.

• eventually come to a stop.

• change its momentum.

• accelerate.

Multiple Choice

Pushing a child on a swing is easier than pushing an adult on the same swing, because the adult has more mass.

• Newton's 1st Law

• Newton's 2nd Law

• Newton's 3rd Law

• None of them

Multiple Choice

Rockets are launched into space using jet propulsion where exhaust accelerates out from the rocket and the rocket accelerates in an opposite direction.

• Newton's 1st Law
• Newton's 2nd Law
• Newton's 3rd Law
• None of them

Poll

How confident do you feel about the material we just reviewed?

• Very confident. I am ready for the assessment!

• I understand most of it, but there are some things I need to study.

• Neutral. I understand some of it, but I need to review quite a bit.

• Overall, I am more confused than confident. I need to review a lot more.

• I am totally lost. I do not understand any of this material.