Motion, Forces, and Energy

In order to do work on an object, the force you exert must be

• the maximum force you can exert

• in the same direction as the object's motion

• in a direction opposite to Earth's gravitational force

• quick and deliberate

What do machines do?

• change the amount of force you exert or the distance over which you exert the force

• increase the amount of work that is done

• decrease the amount of work that is done

• eliminate friction

Visible light is an example of

• chemical energy

• electrical energy

• thermal energy

• electromagnetic energy

The energy associated with motion is called

• force

• kinetic energy

• potential energy

• nuclear energy

The Law of Conservation of Energy states that when one form of energy is converted into another

• energy is destroyed in the process

• no energy is destroyed in the process

• energy is created in the process

• some amount of energy cannot be accounted for

Which of these is an example of work being done on an object

• holding a heavy piece of wood at a construction site

• trying to push a car that doesn't move out of deep snow

• pushing a child on a swing

• holding a door shut on a windy day so it doesn't blow open

If you exert a force of 20 newtons to push a desk 10 meters, how much work did you do?

• 200 joules

• 30 joules

• 10 joules

• 100 joules

Which of these simple machines is an inclined plane wrapped around a cylinder?

• lever

• screw

• wheel and axle

• pulley

Unlike kinetic energy, potential energy is

• energy of motion

• not measureable

• conserved

• stored

A change from one form of energy into another is called

• potential energy

• work

• the output force

• energy transformation