13 Work, Power, Machines

How many classes of levers are there?

• 3

• 4

• 5

• 6

The fulcrum is in the middle of a

• 1st class lever.

• 2nd class lever.

• 3rd class lever.

• 4th class lever.

The input force or effort is in the middle of a

• 1st class lever.

• 2nd class lever.

• 3rd class lever.

• 4th class lever.

The output force or load is in the middle of a

• 1st class lever.

• 2nd class lever.

• 3rd class lever.

• 4th class lever.

Scissors are a type of

• simple machine.

• compound machine.

The simple machines that are found in common scissors are

• pulley and inclined plane.

• pulley and wedge.

• wedge and lever.

• lever and wheel and axle.

Weight is a force.

• True

• False

Weight is the force of gravity acting on a

• mass.

• Newton.

• force.

• mechanical advantage.

A device that helps make work easier is called a

• mechanism.

• joule.

• calculation.

• machine.

An inclined plane make work easier by increasing the

• force.

• distance.

• work.

• time.