Simple Machines
and Compound Machines
Lever
To calculate mechanical advantage: output force/input force
To increase mechanical advantage: Make the lever longer or move the fulcrum closer to the load.
Pulley
To calculate mechanical advantage: MA is equivalent to the number of pulleys
To increase mechanical advantage: Increase the number of pulleys
Wheel and Axle
To calculate mechanical advantage: radius of wheel divided by radius of the axle
To increase mechanical advantage: Increase the radius of the wheel
Inclined Plane
To calculate its mechanical advantage: Length of inclined plane divided by height of load raised
To increase its mechanical advantage: Increase the length of inclined plane
Wedge
To calculate mechanical advantage: length of wedge divided largest thickness of wedge
To increase mechanical advantage: Increase the length of the wedge and make it thinner
Screw
To calculate mechanical advantage: First unwind the screw(inclined plane)
Then divide the length of the inclined plane by its height
To increase mechanical advantage: Make the spiral on the screw longer and closer to the threads
Compound Machines
The mechanical efficiency of most compound machines is low. This is because compound generally have more moving parts which means more friction. Friction lowers the output work.