WORK AND ENERGY

WorkWork is said to be done whenever the application of the force produces a change.

A change can be the change invelocity

position

shape

temperature

ENERGY

The ability to do work is called energy.

Different Kinds of Energy

Kinetic Energy

Potential Energy

Kinetic Energy

The ability to do work based on motion is called kinetic energy

Potential Energy

The energy possessed by objects because of their position or shape.

Identify Kinetic and Potential Energy

An object can have both potential and kinetic energy.

An aeroplane flying at a height has both potential and kinetic energy

The sum of the potential and kinetic energies of an object is called mechanical energy.

Energy can neither be created nor destroyed.

It can only be converted from one form to another or transferred from one object to another.

Rubbing Palms produces heat energy.

Work- Formula

How much work is done – depends on the force applied to produce the motion.

The amount of work done

Depends on The force applied to do the work.

The distance travelled

Therefore work done= force X distance

Unit of Work

Unit of Force- Newton

Unit of Distance- Meter

Therefore, the unit of Work= Newton-meter

Newton-meter is also called Joule in the name of British scientist James Joule.

Work done in lifting mass to a height

Earth attracts the mass m with a force = mg

g is the acceleration due to gravity.

h is the distance through which the object has moved.

Work done…

Therefore the work done in raising the books of mass m to height h is mgh.