Force

A force acting on an object does no work if

• a machine is used to move the object.

• the force is not in the direction of the object’s motion

• the force is greater than the force of friction

• the object accelerates

Force is

• a push or pull that causes an object to move, stop, or change direction

• the reason the Star Wars movies were made

• a balanced force

• unbalanced forces

Scientists express force by using a unit called the

• Joule (J)

• Newton (N)

• Kg/m

• Pound (lb)

If the distance between two objects increases, the gravitational force pulling them together increases.

• True

• False

The two factors that affect the acceleration due to gravity are ________ and ________.

• Size, distance

• Distance, mass

• Weight, speed

• Mass, force

_____ is the rate at which velocity changes.

The amount of friction between two surfaces depends on two main factors. One is how _____ the surfaces are that are in contact. The other factor is the _____ pushing the surfaces together.

For every action there is an equal but opposite reaction is

• Newton First Law of Motion

• Newton Second Law of Motion

• Newton Third Law of Motion

• The law of conservation of momentum

Total distance divided by total time is

• acceleration

• Constant speed

• average speed

• positive acceleration

A force acting toward the center of a curved or circular path is called

• balanced forces

• net force

• gravity

• centripetal force