CLASS: IX NCERT (CBSE)
Work and Energy
SUMMARY
• The essential conditions to be satisfied for work to be done are:
Some force must act on the object
The point of application of force must move in the direction of force
W = F x S
• SI unit of work is joule
• Energy is the capacity to do work
• The two types of mechanical energy are kinetic energy and potential energy
• Kinetic energy is the energy possessed by an object by virtue of its motion
• Potential energy is the energy possessed by an object by virtue of its position or condition
Kinetic energy
Potential energy = mgh
• Law of conservation of energy states that energy can neither be created nor destroyed but can be transformed from one form to another
• Power is the rate of doing work
• SI unit of power is watt
