Examples of Work Work is done on a ball when it is lifted to a height above the ground The weight on the ball produced by the gravitational field does work on the ball over a distance equal to the height of the ball Work is done when a bird flies through the air Air resistance (drag) does work against the bird as it flies through the air

Examples of work include lifting an object against the Earth’s gravitation, driving a car up a hill, and pulling down a captive helium balloon. Work is a mechanical manifestation of energy. The standard unit of work is the joule (J), equivalent to a newton – meter (N · m).

If work is done on the system, the work is negative (i.e., energy added to the system). Examples of the work done by the system are, The output from the turbine. A rocket is being launched. A pump used to draw water. A vehicle running with an Internal Combustion Engine.

Work done in compressing a gas at constant temperature may be expressed as the product of pressure P times the change in volume dV; that is, W = PdV. Work done by a torque T in rotating a shaft through an angle φ may be expressed as the product of the torque times the angular displacement; that is, W = T φ.

The amount of work done on the object is equal to the amount of energy transferred to it. Examples: 1. A man applies a force of 700N to a crate and pushes it through a distance of 200 cm. Calculate the amount of work done by the man. 2. Another man pushes a crate as shown with a force of 550N and does 2.2kJ of work.