work and simple machines motion forces and energy definitions for vocab chapter 4

• work
  work is done when a force exerted on a object on an object causes that to object to move some distance; equal to force times distance; measured in joules pg. 98

• power
  rate at which work is done; equal to the work done divided by time it takes to do the work measured in watts pg. 101

•  input force
  force exerted on a machine pg. 104
• output force
  force exerted by a machine pg. 104
• mechanical advantage
  number of times the input force is multiplied by a machine; equal to the output force divided by input force pg. 105
• efficiency
  equals the output work divided by the input work expressed as a percentage pg. 107