Chapter 13: Forces

Force can be described as...

• A push or pull on an object

• A drop or fall of an object

• gravity and it's laws

• objects that contain matter

Newton's Universal Law of Gravitation states...

• An object at rest will remain at rest and an object in motion will remain in motion at constant velocity unless acted upon by an unbalanced force

• The Force on an object is related to both the mass of the object and the acceleration of the object as well. 

• For every action, there is an equal and opposite reaction.

• All objects in the universe attract each other by the force of gravity. 

The achievement of lifting a rocket off the ground and into space can be explained by

• Newton's first law.

• Newton's second law.

• Newton's third law.

• the law of conservation of momentum.

The amount of matter in an object is called its

• inertia.

• mass.

• force.

• balance.

The force of gravity on a person or object at the surface of a planet is known as

• mass.

• inertia.

• air resistance.

• weight.

The force that one surface exerts on another when the two rub against each other is called

• friction.

• acceleration.

• inertia.

• gravity.

The law of universal gravitation states that any two objects in the universe, without exception,

• attract each other.

• repel each other.

• combine to provide a balanced force.

• create friction.

The SI unit for force is the

• newton.

• meter.

• kilogram.

• pound.

What happens when two forces act in the same direction?

• They cancel each other out.

• The stronger one prevails.

• They add together.

• Their sum divided by two is the total force.

When the only force acting on a falling object is gravity, the object is said to be

• stationary.

• decelerating.

• in free fall.

• a projectile.