Answers

2014-10-18T13:10:31+08:00
Kinetic Energy Problems.The Kinetic Energy (Ek) of an object depends on both its mass (m)and its speed (v).What you need to know about Kinetic Energy depends on the paperyou are sitting at the time.At General Level, all you need to know about Kinetic Energy is thatthe greater the mass and/or the speed of a moving object, thegreater its Kinetic Energy. That’s it!For the Credit paper, you must be able to• carry out calculations involving the relationship betweenKinetic Energy, mass and speed.(You need to be able to use the equation !Ek =12mv2)• carry out calculations involving energy, work, power and theprinciple of conservation of energy.(You can be asked to solve problems similar to the lift examplewe looked at in class)The examples in this handout are designed to help prepare you forthe extended style of problems that can appear in the credit paper,since this is where any questions involving calculations about KineticEnergy will appear in the May exams.
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2014-10-18T13:25:13+08:00
Given: m= 45kg & 67kg
            v= 9m/s
Required: KE
Formula: KE= 0.5 (m)(v)^2 =mv^2
                                                2
Solution: 0.5 (45kg + 67kg) (9m/s)^2
               =0.5 (112kg) (9m/s)^2
              =504^2
                 2
              = 254016
             = 127008 J ~final answer

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