Friction opposes motion of objects.

Which object has the weakest gravitational pull? A. fist-sized rock B. piece of paper C. huge truck D. the moon

Friction is produced by a single object

Friction is a (force, energy) that opposes the motion of objects.

Friction acts in a direction the same as the direction of the object’s motion

Friction occurs when the surfaces of the two objects rub against each other

What is always produced when there is energy transformation? A. chemical B. electricity C. heat D. light

A ball rolled after being kicked and slowed down until it stopped. Which of the following forces caused the ball to slow down? A. electrical B. friction C. gravity D. magnetic

Which energy transformation occurs in a flat iron? A. electrical energy to heat B. mechanical energy to light C. chemical energy to sound energy D. chemical energy to electrical energy

Friction always acts (opposite, the same) the direction of the object’s motion

Which of the following statements is TRUE? A. Friction makes objects move. B. Friction stops moving objects. C. Friction has no effect on moving objects. D. Friction allows moving object to continue moving.

Friction causes moving objects to stop.