Definitions and units for work, energy and power Different forms of energy and energy conversions Mass as a form of energy Principle of conservation of energy Percentage efficiency
ACTIVITIES: Demonstration of an energy conversion Estimation of average power developed (person running upstairs or repeatedly lifting weights)
SCIENCE,TECHNOLOGY AND SOCIETY: Work done by lifts and escalators Sources of energy (renewable and non-renewable) Mass transformed to other forms of energy in the Sun Efficient use of energy in the home Power of devices (light bulbs, motors)
PHYSICAL QUANTITIES INTRODUCED IN THIS CHAPTER: Quantity
work energy
potential energy kinetic energy power
Symbol W E
Ep Ek P
Name of SI unit joule joule joule joule watt
Symbol for unit J J J J
W
1 2
Po 100 Pi
Work
Kinetic energy Potential energy
Mass-energy equivalence
Principle of conservation of energy Principle of conservation of energy
