Skip to content
Smartable Academy
Smartable tools

← Work, Energy, and Simple Machines

Your progress

Checking your sign-in…

Who's learning?

Each profile keeps its own read lessons, badges, streak, and practice scores on this device.

Lesson 6 of 14

A machine trades force for distance

Show on a big screen

7 min

Text size

A 600 N barrel must reach a platform 2 m high. What can you do besides lifting it straight up?

Loading lab…

A steep ramp needs 600 N over a 2 m push.
Step 1 of 4
  1. A steep ramp needs 600 N over a 2 m push.
  2. A medium ramp needs 200 N over a 6 m push.
  3. A gentle ramp needs 75 N over a 16 m push.
  4. Same load, same rise, less force.

Rule

Push it up a ramp. You use less force, but you push over a longer distance.

A simple machine changes the size or direction of the force. It does not reduce the work. Advantage is short for mechanical advantage. Advantage = load ÷ effort.

  • Effort — the force you apply.
  • Load — the force you must overcome.
  • Mechanical advantage — load ÷ effort.

Think of a ramp with no friction. The push does work effort × length. The lift needs work load × height. With no friction these are equal. Then effort × length = load × height.

Divide both sides by effort × height. Then load ÷ effort = length ÷ height. So the advantage is length ÷ height.

A ramp is 8 m long and 2 m high. Advantage = 8 ÷ 2 = 4. A 600 N load needs 600 ÷ 4 = 150 N.

Try the lab to finish this lesson.