• To obtain the experimental relationship between effort and distance moved by effort, and to compare with a theoretical prediction.
  • To show that the work done is the area under a graph of load against distance moved.


  • Table unit for experiments on mechanical work and potential energy.
  • Lifting a weight using a lever and a dynamometer (spring balance).
  • Integrated angle measuring scale protractor.

The apparatus consists of the arm, hanger with loads, spring balance and protractor scale attached to the support board. The apparatus mainly focuses on the fact that work done by a variable force can be determined by measuring the area under the graph of force and distance traveled. One end of the arm is fixed and its position is indicated by the protractor. Other end of arm carries the load hanger, and is restrained by spring balance that is perpendicular to the arm. Under the application of load, the movement of arm can be read easily.

This experiment is designed to reinforce the general principle that the work done, particularly by a variable force, can be determined simply by measuring the area under the graph of force and distance moved.

Vertical Force

The apparatus is a simple lifting mechanism with obvious non linear characteristics. A suspension cord carrying a loaded trolley at mid span is tensioned by passing the cord over a pulley at one end and down to a weight hanger. As the vertical effort is increased, the tensioned cord will move to a new equilibrium position lifting the loaded trolley. Heights of the load and effort are measured relative to the base. All the pulleys are fitted with ball bearings to minimize friction effects.

Tangential Force

A pivoted arm carrying a load hanger at its end is restrained by a force gauge at right angles to the arm. The angular position of the arm is indicated by a protractor scale attached to the backboard.

The effort is the force needed to hold the weighted arm at a particular angle. This can be repeated for several different weights.