A rubber ball is dropped from a height of 5 m on a planet where the acceleration due to the gravity is not known. On bouncing it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of:
Correct answer: B. 2/5
- A. 16/25
- B. 2/5
- C. 3/5
- D. 9/2
Explanation
According to the law of conservation of energy energy, can neither be created nor be destroyed. Therefore, Loss in PE = Gain in KEHence, 1/2mv² = mghFrom this equation, we get the formula of velocity asv = √2ghv1/v2 = √h1/√h2Hence, the correct answer is 2/5 according to the explanation given below.
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About Work and Energy
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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