Motion (Science 8)

The first law of motion states:

• An object at rest will stay at rest

• An object in motion will stay in motion

• An unbalanced force can change the velocity of an object in motion

• All of the above

Newton's first law of motion is also known as

• the law of universal gravitation

• the law of unbalanced forces

• the law of inertia

A ball is rolling down a level sidewalk. As it rolls it slows down and stops. Why?

• A frictional force acts on the ball to stop it

• The net force on a moving ball is always zero.

• The force that started it moving was taken away.

Gravity accelerates objects on Earth at which rate?

• 8 m/s²

• 9.8 m/s²

• 900 m/s²

Newton's third law of motion involves

• one force acting on an object

• a force pair acting on two different objects

• unbalanced forces acting on many objects

The momentum of an object depends on what two factors?

• force and acceleration

• mass and acceleration

• mass and velocity

Which is an example of a noncontact force?

• a bat hitting a ball

• the pencil and your paper

• metal being attracted to a magnet

What is a force?

• a push or a pull

• the constant motion of an object

• the acceleration of an object

• the mass of an object

Intertia depends on ...

• Weight

• Velocity

• Mass

• Acceleration

Newton's second law of motion states

• If there is more mass then there is more acceleration

• An object at rest wants to be in motion

• Force = Mass x Acceleration