Which calculation gives a machine's mechanical advantage?

Which action does work on a school bag?

Ana moves her hand along a lever to compare the pushes needed to lift a load. Which plan makes this a fair test?

Use the arm lengths shown. What is this lever's ideal mechanical advantage?

Ignoring friction and the plank's weight, what effort balances the pictured load?

Liza pushes the effort end of the pictured lever downward. In which direction does the load begin to move?

Ben keeps both ends of a lifting lever in the same places. Where should he move the fulcrum to reduce the effort needed?

The diagram models a fishing rod held at one end. What benefit does this arrangement provide?

Which part of ordinary pliers serves as the fulcrum?

A nutcracker holds a nut between its hinge and the points where hands squeeze its handles. Which class of lever is it?

Ignoring friction, how does the pictured pulley affect the direction and strength of the applied force?

Ignoring friction and the pulley's weight, what is the ideal mechanical advantage of this setup?

Use the force values shown. What mechanical advantage does this pulley system provide?

Carlo must raise the same heavy sack using different pulley arrangements. Ignoring friction and pulley weight, which requires the smallest pull?

Ignoring friction and pulley weight, how large a pull is needed to raise the pictured load at a steady speed?

Use the radii shown. What is the ideal mechanical advantage when effort turns the larger part?

A wheel's radius stays the same while its axle becomes wider. What happens to its ideal mechanical advantage when effort is applied to the wheel?

Which simple machine does a round doorknob use to turn its central shaft?

A machine produces 30 N from an input of 60 N. How does its mechanical advantage compare with 1?

An ideal lever reduces the force needed to lift a load. What must the user do in return?