Forces and Motion Review

Forces and Motion Review

Types of Forces

Forces can be categorized as:

1) Contact Forces

2) Non Contact Forces

Multiple Choice

A contact force is from

• objects physically touching

• far apart objects

• not touching object

• always a pull

Multiple Choice

A non-contact force is between

• two objects that aren't touching

• two objects that are touching

• the ground and wheels

• you and me

Multiple Choice

Applied force is an example of a _________________ force.

• contact

• non-contact

• balanced

• unbalanced

Multiple Choice

The force between the phone and the mount is a

• contact force

• non-contact force

Multiple Choice

Gravity is a

• Contact Force

• Myth

• Non-contact Force

Friction

A type of force that happens between two objects that come in contact with one another.

Friction is an opposing force. It acts in the opposite direction of motion.

You must overcome friction to make stationary items move.

Multiple Select

What type of force is friction?

• Contact force

• Non-Contact force

Friction

The amount of friction force acting on an object depends on the weight of the object and the roughness of the surface that the object is in contact with.

Multiple Choice

Rougher surfaces have ...

• greater friction
• less friction
• the same level of friction

Multiple Choice

The amount of friction depends on the weight of the objects pressing together.

• True

• False

Balanced and Unbalanced Forces

When the forces acting on an object are equal, they are called balanced forces. Balanced forces cancel each other out.

When the forces acting on an object are not equal, the forces are unbalanced. Unbalanced forces put things in motion.

Net Force

It is the sum of all forces acting on an object.

Multiple Choice

Is the Net Force balanced or Unbalanced?

• Balanced

• Unbalanced

Multiple Choice

What is the net force and to what direction.

• 210 N to the right

• 280 N to the right

• 110 N to the left

• 180 N to the left

Multiple Choice

How do you find the net force of this image.

• Add up all the arrows

• Add a green arrow and the orange arrow.

• Subtract all the arrows.

• Add the green arrows and subtract the orange arrow.

Multiple Choice

Is this a balanced or unbalance force?

• Balanced
• Unbalanced
• Neither one
• Both

Multiple Choice

Calculate the net force of the object in the image shown.

• 20N
• 35N
• 5N
• 25N

Motion

Forces Put Things in Motion

Multiple Choice

What type of forces put things in motion?

• Balanced

• Unbalanced

Describing Motions

• Velocity-speed and direction of an objects motion

• Acceleration- change in speed or direction of an objects motion

• Speed-distance an object has traveled in a given amount of time.

• Motion Graphs- describe the motions an object has taken.

Multiple Choice

Which runner had a head start?

• A
• B
• C

Multiple Choice

What does this graph represent?

• Constant speed
• Acceleration
• Not moving

Multiple Choice

What does this graph represent?

• Constant speed
• Acceleration
• Not moving

Newton's Laws of Motion

Three laws that describe how forces interact with objects and cause motion

1st Law of Motion

Objects at rest, remain at rest. Unless acted upon by an outside force.

Objects in motion, remain in motion. Unless acted upon by an outside force.

Open Ended

What is Isaac Newton telling us with this first law? Put the first law of motion in your own words.

2nd Law of Motion

The acceleration of an object depends on the net forces acting on the object and (inversely on) the mass of the object.

F = M x A

(force) = (mass) x (acceleration)

2nd Law of Motion

In simple term: to move a mass, you need a force.

More force=More acceleration

or we can say,

The more massive an object is the more force is needed to make the object accelerate.

3rd Law of Motion

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

Multiple Choice

Which of Newton's Laws is illustrated with a large mass and a small mass accelerating?

• 1st Law, the Law of Inertia.
• 2nd Law, the Law of Acceleration
• 3rd Law, the Law of Action Reaction
• The Law of Conservation of Mass

Multiple Choice

When a cannon fires a cannonball we observe Newton's third law. Which force is the reaction force?

• The cannon moving forward
• The cannonball moving forward
• The cannon moving backward
• The cannonball moving backward

Multiple Choice

A person is pushed forward into their seat belt when a car stops.  Which law is this?

• 1st
•  2nd
• 2 and 3
• 3rd 

Multiple Choice

This equation goes with which law?

• Newton's first law of motion

• Newton's second law of motion

• Newton's third law of motion

• None of these

Multiple Choice

Newton's third law states that any action will have a(n) _______ and ______ reaction

• Equal and similar

• Equal and opposite

• Equal and different

• Greater and opposite

Multiple Choice

What is Newton's First Law

• F=ma

• Every action has an equal and opposite reaction

• An object at rest stays at rest, an object in motion stays in motion.

• Friction

Multiple Choice

If a force of 26 N is exerted on two balls, one with a mass of 0.52 kg and the other with a mass of 0.78 kg, which ball will have the greater acceleration? (F=ma)

• The one with a mass of .78 kg will have the greatest acceleration.

• The one with a mass of .52 kg will have the greatest acceleration.

• They will both accelerate at the same rate.