Laws of Motion and Gravity

Two students pull on the opposite ends of a rope, but neither student is able to move the other. Which statement best explains why neither student is moved?

• The each pull on the rope with the same amount of force, so the net force is zero.
• They each exert the same amount of friction against the ground, so the net friction is zero.
• Their forces are not balanced, but gravity keeps them from moving
• The two students have the same mass.

A horizontal force of 24 N is being applied to a box on a level surface. The box is accelerating at the rate of 2.0 m/s² against a frictional force of 14 N. What is the mass of the box?

• 5.0 kg
• 7.0 kg
• 12.0 kg
• 19 kg

A student pushes a book with a force of 5 N to the east. Which statement describes the reaction force?

• 5N eastward, acting on the book
• 5N westward, acting on the book
• 5N eastward, acting on the student
• 5N westward, acting on the student

A 3.0 N force and a 5.0 N force are acting in opposite directions on the same 5.0 kg ball. What is the magnitude of the acceleration of the ball?

• 0.40 m/s_²
• 0.63 m/s_²
• 1.6 m/s_²
• 2.5 m/s_²

Student X pushes a 10 N box with a force of 2 N towards Student Y. At the same time, Student Y pushes the same box with a 6 N force in the opposite direction. Which would most likely occur?

• The resultant force on the box would be 8 N.
• The resultant force on the box would be 18 N.
• The box will move toward Student X.
• The box will move toward Student Y.

The action of swimmers using their arms to generate action and reaction forces which propel themselves through the water is an example of what law?

• Newton’s First Law of Motion
• Newton’s Third Law of Motion
• Law of Conservation of Linear Momentum
• Law of Conservation of Angular Momentum

When a hammer strikes a nail, the nail

• exerts balanced forces that helps it from moving.
• exerts a force equal to the weight of the hammer.
• exerts an unbalanced force that changes its velocity.
• exerts an equal and opposite force back on the hammer.

Which object will have the greatest acceleration if acted upon by a net force of 100 N?

• 5-kg object
• 25-kg object
• 50-kg object
• 100-kg object

The property of matter that resists changes in motion is called

• inertia.
• friction.
• gravity.
• weight.

 What is the net force on the box?

• 7 N up
• 8 N up
• 8 N down
• 22 N down