Forces and Motion Review

Friction is:

• a force that opposes motion (slows things down).

• not a force.

• a forces that decreases with mass.

• a force that does not exist on a smooth surface.

Rolling friction:

• is greater than sliding friction.

• is less than sliding friction.

• makes objects harder to move.

• is the same as air resistance.

What is true about forces?

• A force is a push or a pull.

• A force is expressed in Newtons.

• A force can make an object speed up, slow down, or change direction.

• All of the above.

What type of friction causes a parachutist's acceleration to change when he jumps out of a plane?

• sliding

• rolling

• fluid

• static

What is the net force when you combine a force of 10 N to the left with a force of 2 N to the right?

• 12 N to the right

• 12 N to the left

• 8 N to the right

• 8 N to the left

This force opposes motion between objects that are touching (slows things down):

• gravity

• friction

• velocity

• speed

What can you add to highways to increase friction between the road and the car tires?

• sand

• oil

• ice

• water

What kind of friction will wear down tires on a car?

• sliding friction

• rolling friction

• fluid friction

• static friction

Distance divided by time is the formula to calculate:

• net force

• gravity

• speed

• acceleration

A change in speed, velocity, or direction is:

• gravity

• acceleration

• a special force

• friction