1. Momentum Revision

2. Define: Work: Physical scalar quantity that equal mass multiplied by displacement Energy: ability to do work Kinetic energy: ability to do work due to motion Potential energy: ability to do work due to chamngeof position or shape Efficiency: ratio of useful energy to total energy Momentum: mass in motion or vector physical quantity that equals mass multiplied by velocity

3. State Law of conservation of energy: energy cannot be created or destroyed, but converted from one form to other Law of conservation of momentum: momentum before collision equals momentum after collision Work energy theorem: what we lose as energy we gain as work

11. A 10 kg object moving at 5 m/s collide with a 20 kg coming from the opposite direction at 8 m/s,the first object rebound back at 4 m/s, calculate the velocity of the second object

12. A 10 kg object moving at 5 m/s speed up to 20 m/s and cover 50m, calculate the force

13. Examples: 800 J of energy is supplied to an electric generator, 420 J converted to heat, and 180 J converted to sound, Draw the Sankey diagram and calculate the efficiency of the generator. 800J 420 J 180J 800-(420+182) = 200

14. What do we need to know to calculate the velocity of the plane? No. of particles Mass of each particle Velocity of particles Mass of the plane

15. A 25000 kg jet ejected 2500 kg of gas at 80 m/s, what will be the velocity of the plane?