Newton's Laws of Motion

Two people are trying to push a large box across a

floor. Each person pushes with an equal amount

of force. The total amount of force they exert on the box is

500 newtons. Despite their efforts, the box will not move. What is the amount of force exerted by the box on each person?

• 0 newtons

• 250 newtons

• 500 newtons

• 1500 newtons

A student pushes a hollow ball with a small amount of force causing it to roll quickly across the room. The student then pushes a solid ball with the same amount of force. Which statement demonstrates an understanding of force and its e ects on an object?

• The force on both balls was the same; therefore each ball pushes back with the same amount of force.

• The force on both balls was the same; however each ball pushes back with a different amount of force.

• The solid ball pushes back with a greater force than the hollow ball, because the solid ball has a greater mass.

• The hollow ball pushes back with a greater force than the solid ball, because the solid ball moved faster and

  further.

The picture shows a student pulling on a rope that is attached to a wall. Which statement correctly describes the amount of force applied by the wall as the student continues to apply a 250-newton force?

• The wall pulls with a force of 125 newtons against the student.

• The wall pulls with a force of 250 newtons against the student.

• The wall exerts twice as much force as the student.

• The wall exerts no force since it is stationary.

A spring scale is pulled downward and readings are recorded. If the spring is pulled 3.5 cm, the spring scale should read

• 12N

• 13N

• 14N

• 15N

A force is acting on each of the objects shown. What can be concluded about these forces?

• They are the same because they point toward the objects.

• They are the same because they have the same magnitude.

• They are different because they have different magnitudes.

• They are different because they have different directions.

A ball is dropped from the top of a tall building. As the ball falls, the upward force of air resistance becomes

equal to the downward pull of gravity. When these two forces become equal in magnitude, the ball will

• flatten due to the forces

• fall at a constant speed

• continue to speed up

• slow to a stop

Four forces are acting on a box, as shown. This box will increase in speed

• downward and to the left.

• downward and to the right.

• upward and to the left.

• upward and to the right.

A 10-newton force and a 15-newton force are acting from a single point in opposite directions. What additional

force must be added to produce equilibrium?

• 5 N acting in the same direction as the 10-N force

• 5 N acting in the same direction as the 15-N force

• 10 N acting in the same direction as the 10-N force

• 25 N acting in the same direction as the 15-N force

Automobiles, baseballs, skateboards and bicycles - the world is full of things that are in motion. Centuries ago

the British physicist Sir Isaac Newton stated three laws that describe the ways in which things move. These are

Newton's three laws of motion:

The first law: Unless acted upon by an outside force, a body at rest tends to stay at rest, and a body in motion tends to stay in motion.

The second law: Acceleration is equal to the net force acting on a body divided by its mass.

The third law: For every action force there is an equal and opposite reaction force.

A driver starts her car and steps on the gas pedal. The car gradually accelerates to 50 km/hr. A few minutes later,

the driver suddenly slams on the brakes to avoid hitting a box in the road. As the car comes to a stop, the driver's

body appears to lurch forward in the seat until it is restrained by the seat belt.

What law best explains why the driver's body appears to lurch forward when the brakes are suddenly applied?

• Newton's first law

• Newton's second law

• Newton's third law

• The law of gravity

Use the diagram to answer the question. A marble was rolled down the ramp as shown in the diagram above. What path will the marble take after it rolls off the ramp?

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