A car of mass 800kg accelerates from 20ms-1 to 30ms-1.The increase in kinetic energy will be;
Correct answer: B. 200 kJ
- A. 2 J
- B. 200 kJ
- C. 200 J
- D. 2 kJ
Explanation
Use formula K.E = ½ mv² for both speeds separately.½ mv²½ (800)(30)² = 360000--------- ½ mv²½ (800)(20)² = 160000Change in K.E = 360000 - 160000 = 2000
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Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
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