Newton's Laws of Motion

Forces occur in pairs. The first force is called the action force. The second force would be called the:

• moving force

• momentum force

• reaction force

• kinetic force

If you are wearing roller skates and you push against a wall, you roll backwards. Why?

• The wall is bigger than you are, so it pushes you with a greater force than you push it.

• Every action has an equal and opposite reaction.

• There is no friction between your roller skates and the floor.

• You and the wall have opposite charges, so the wall repels you

An object is accelerating when _______________.

• it is not moving

• it is spinning around

• it is changing speed or direction

• it continues at the same speed

Suppose an astronaut floating in space throws a rock. What will happen to the rock?

• It will continue to move in the same direction but will eventually slow down and stop.

• It will continue to move in the same direction, speeding up as it moves.

• It will continue to move at constant speed in the same direction until it is acted on by another force.

• It will go into orbit around the astronaut.

When one figure skater pushes on another, both skaters move in opposite directions. Which of Newton's laws of motion best explains why this occurs?

• Newton's First Law

• Newton's Second Law

• Newton's Third Law

• Newton's Fourth Law

A satellite in orbit is considered to be accelerating because:

• A satellite in orbit is considered to be accelerating because:

• it keeps moving faster and faster.

• it is constantly changing its direction of motion.

• it is moving in a straight line with a constant speed.

Suppose you were to fill a balloon with air then let go of it without tying it closed. What causes the balloon to fly away?

• Your breath contains helium, which is lighter than air.

• The balloon's movement is the reaction to the force of air escaping.

• The warm air from your breath is less dense than the cooler air around the balloon, and warm air always rises.

• The air around the balloon is under higher pressure, so it pulls the balloon forward.

What is the mass of a stone that accelerates at the rate of 2 meters/second^2 when a force of 500 N is placed on it?

 $F=ma;\ \ a=\ \frac{f}{m}\ ;\ or\ \ \ m\ =\frac{f}{a\ \ }$  

• 25 kg

• 250kg

• 1,000kg

• 2,000kg

While you’re ice-skating with your friends, you push off from one end of the rink and slide forward. Based on Newton’s first law of motion, what is true?

• You will lose your balance and fall over before you reach the middle of the ice rink

• You will continue to slide across the ice until a force makes you stop or change direction.

• The force of gravity will make you keep your velocity until your friends make you stop.

• The size of your ice skates will determine how quickly or slowly you travel across the ice.

What is inertia?

• the amount of force necessary to make an object at rest start moving

• an object’s velocity combined with its friction

• what keeps an object steady, whether at rest or moving at the same velocity

• the amount of friction necessary to slow down an object in motion