A push or pull between objects.

• Force

• Friction

• Newton (N)

• Vector Quantity

A force that opposes the motion of an object.

• Friction

• Balanced force

• Vector quantity

• Sir Isaac Newton

Two or more forces that act on an object without causing a change in the object's motion.

• Balanced forces

• Unbalanced forces

• Static friction

• Kinetic friction

Balanced or Unbalanced?

A fish is hooked on a line and reeled in by the fisherman.

• Balanced

• Unbalanced

Balanced or Unbalanced?

A car driving on the highway slows down quickly because of the traffic ahead.

• Balanced

• Unbalanced

Balanced or Unbalanced?

A ball sits at the top of a hill, but doesn't roll down.

• Balanced

• Unbalanced

If I kick a soccer ball across the field, what vocabulary word tells me why the ball would slow down in the grass?

• acceleration
• friction
• gravity

Can speed and direction change?

• No

• Yes

Any change in speed and direction is called...

• acceleration

• action

Does the size of a force affect an object's acceleration?

• No

• Yes