HW 5-10

material with _______________ surfaces have less friction

• smooth

• rough

• both

you can walk because there is friction between your __________ and ______________

• ground and air

• feet and ground

• feet and air

• air and ground

Which motion has less friction

• Sliding on grass

• Sliding on ice

How can a sailboat increase its water resistance?

• Make the sail bigger

• Make the sail smaller

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

• Brakes used on a bike

• car tires on the road

• Catching objects

• All of them

How does friction affect speed?

• more friction decreases speed
• more friction increases speed
• less friction decreases speed

Rougher surfaces have ...

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

The rougher the surface, the faster an object will travel over the surface.

• True
• False

Which is easier to skate on?

• ice

• sand

Friction is a force created by-----

• pushing

• rubbing

• gravity