Friction

Force the opposes motion between 2 surfaces

• force
• Newton
• friction
• net force

What are 2 factors that determine the amount of friction between 2 objects?

• Force and roughness between surfaces
• hills and valleys and how smooth or rough the surface is
• Amount of force and amount of surface the comes in contact
• The force and the weight exerted on the surfaces

Which of the following is an example of friction that is helpful?

• Brakes used on a bike
• Tires from a car on the road
• Tread on the bottom of your shoes
• All are examples that are helpful

Which of the following is an example of friction that is harmful?

• Pencil marking on paper
• Engine parts wearing out
• sand placed on ice in the winter
• Using an eraser to erase marks

Which would NOT be a way of reducing friction?

• making the surfaces smoother
• using lubricants such as waxes, oils, or grease
• changing from sliding friction to rolling friction using ball bearings
• Using kitty litter on snow and ice to help your car gain traction

How does friction affect speed?

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

Friction is a force that acts in an ___________ direction of movement.

• similar
• opposite
• parallel
• west

A type of friction that occurs when air pushes against a moving object causing it to decelerate.

• surface area
• air resistance
• velocity
• gravity 

What does friction produce?

• light
• sound
• heat
• gravity

What is the bowling alley lane coated with to reduce friction?

• oil
• wood
• paint
• sand