Level 7 - Chapter 13 Chapter Test

What is the rate at which work is done?

• force

• power

• efficiency

• mechanical advantage

Dividing the output force by the input force gives you what value?

• power

• work

• mechanical advantage

• efficiency

How can you increase a machine’s efficiency?

• reduce friction

• increase force

• increase distance

• decrease mechanical advantage

A worker uses a lever to move a statue. He rests the lever against a stone to give him a mechanical advantage. In which way is the stone being used?

• as an arm

• as a fulcrum

• as a wedge

• as a pulley

When you bite into an apple, your front teeth act as what type of simple machine?

• screw

• lever

• pulley

• wedge

How does a fixed pulley make work easier?

• increases the effort force

• decreases the mechanical advantage

• changes the direction of the force

• decreases the efficiency of the work

Why does a compound pulley provide a greater mechanical advantage than a fixed pulley?

• Because it reduces friction.

• Because it increases the distance over which the force is applied.

• Because it allows the load to be lifted with less effort.

• Because it changes the direction of the force.

You are trying to pry off the top of a paint can using a screwdriver as a lever. Why would it be better to use a 30 cm screwdriver than a 15 cm screwdriver?

• Because a longer screwdriver increases the force applied, making it easier to open the can.

• Because a shorter screwdriver is harder to hold.

• Because a longer screwdriver is heavier.

• Because a shorter screwdriver can break easily.

If a machine cannot increase the amount of work produced, what is an advantage of using it?

• It can change the direction of a force

• It can create energy

• It can increase the total work done

• It can reduce the need for energy

The human arm is a third-class lever because:

• the effort is applied between the fulcrum and the load.

• the fulcrum is between the effort and the load.

• the load is between the fulcrum and the effort.

• it does not act as a lever.