Bundle 1: Newton's Third Law of Motion

A baseball bat hits a baseball with a force of 100 Newtons. What is the force and its direction exerted by the ball on the bat?

• 100 Newtons, same direction

• 100 Newtons, opposite direction

• 200 Newtons, same direction

• 200 Newtons, opposite direction

According to Newton’s Third Law, if someone jumps off a skateboard, the skateboard will roll backwards because -

• the mass of the skateboard is the same as the mass of the person jumping off.

• the pull of gravity on the person is the same as on the skateboard, regardless of size.

• the air resistance on the person is great and the friction on the skateboard is small.

• for the force that sent the person forward, there is an equal force pushing back on the skateboard.

The nozzle of a rocket is pointed downward so that as fuel is ignited, the exhaust pushes downward. Why is this arrangement necessary for a rocket to function properly?

• The rocket is protected from the heat of the exhaust.

• Burned fuel can be collected on the ground.

• As fuel is combusted, the rocket pushes the gases backward and the gases push the rocket forward.

• This allows the rocket to be steered properly.

Newton's third law describes action and reaction forces. A table of four scenarios is provided.

Which of the scenarios described in the table show equal and opposite reaction forces?

• The rocket and balloon

• The rocket and train

• The balloon and girl

• The train and girl

The head of a hammer is often made of steel. This makes the head heavy, which helps create a strong force for driving nails. Steel is also strong. The head of a hammer must be strong to resist what force?

• The force of the air resistance on the moving hammer

• The force of the person using the hammer

• The force of gravity pulling down on the hammer

• The force of the nail pushing in the opposite direction