simple machines and the body

machines provide us a

• mechanical advantage, MA, to help us do work - by multiplyig our force of giving us a speed or distance advantage

• ideal MA (mechanical advantage) excludes the effect of friction

machine advantage

• W = weight moved

• E = effort put in

work

• equals force times distance

energy if no friction

• energy is conserved, therefore, input work = output work

force and distance of a machine

• the force times distance put into the machine is equal to the force times distance you move the resistance

• WITH FRICTION: your input has to be greater than the output because some turns to thermal energy

• if you can use less force to move a larger object, ou will have to move a larger distance than the object moves.