1. Simple Machines
• Make work easier
• Many are similar (are cousins of
each other)
• Can be put together= compound
machine

2. How do they make work
easier?
1. By changing force needed to move
something
2. By changing the direction of the
force
3. Or by doing both
4. By changing the speed at which
work is done

3. Mechanical Advantage
• The amount the force gets multiplied
by a machine
• It is a ratio so it has no units
• Formula= Resistance (output) force
divided by Effort (input) Force

4. Do machines allow you to multiply
work?
• Work= energy
• Energy can not be multiplied, just used
• Efficiency compares work output to work
input
• If they are efficient they _________?
• If they are not efficient (inefficient) they__?

5. Perpetual Motion?
• Perpetual means forever
http://www.kilty.com/pmotion.htm