What force pulls things towards the Earth?

Which surface is likely to have the *most* friction?

Friction always works in what direction?

What helps reduce friction between moving parts?

A heavier object experiences more of which force?

Which of these is a type of friction?

If you push a box, what force resists your push?

Which of these is *not* a force?

What is the unit of force called?

What happens to friction if you add weight to a box being pushed on the floor?