Friction, Gravity, & Simple Machines Review

How does friction affect speed?

• more friction decreases speed
• more friction increases speed
• less friction decreases speed
• less friction doesn't affect speed

______________________ is the force that resists the motion of two surfaces that are touching.

• gravity

• friction

• force

• non-contact

A person skiing down a hill is an example of ______________ friction.

• static

• sliding

• rolling

• fluid

How can you reduce the amount of friction between 2 objects?

• Increase the gravitational force.

• Increase the amount of force put on the objects.

• Reduce the amount of contact between the two surfaces.

• Add more weight to the objects.

There are four types of friction. What are those four called?

• sliding, rolling, static, and fluid

• slipping, sliding, falling, and fluid

• slipping, sliding, static, and flowing

What type of friction will you see when air or liquid slows an objects movement?

• Rolling

• Fluid

• Static

• Sliding

What type of friction will slow down the rolling soccer ball?

• Fluid

• Sliding

• Rolling

• Static

What is static friction?

• Friction between two surfaces that are moving along side each other.

• Friction between two stationary surfaces or object at rest.

• Friction between any two surfaces.

• Friction that occurs when an object rolls over a surface

Why does static friction exist?

• Because surface have imperfections and adhesion occurs between the two stationary surfaces.

• Because surfaces have imperfections, but adhesion doesn't occur between two stationary surfaces.

• Because surfaces are smoother when you move an object.

• Because surfaces are smoother before you move an object.

A block sitting on the side of a ramp is an example of what type of friction?

• Dry friciton

• Rolling friction

• Fluid friction

• Static friction