Physics-Work Energy and Power

Work :

Force* displacement Cosθ, It is a scalar quantity.

Energy:

Capacity of doing work by a body is called its energy.it is a scalar quantity and its SI unit is joule.

Energy developed in body due to to work done on it is called mechanical energy.

Mechanical energy is of two type:

• potential energy: capacity of doing work developed due to its position or configuration is called its potential energy. ex: energy of stretched or compressed spring, energy of water collected at height, stretched bow

• Kinetic energy: Energy possessed by body due to its motion is called Kinetic energy.

** Flying aeroplane has both potential and kinetic energy.

Principal of conservation of energy

Relation between momentum and kinetic energy:

KE=1/2(m*v^2)=1/2(pv)=1/2((m*v)^2/m)=p^2/2m

Power:

Rate of doing work is called power, W/T

SI unit of power is watt and practical unit of power is called horse power

1 HP=746 watt.