A ball of mass 2kg and another of mass 4kg are dropped together from a 60m tall building. After a fall of 30 m each towards Earth, their respective kinetic energies will be in the ratio of:
Correct answer: B. 1 : 2
- A. 1 : 4
- B. 1 : 2
- C. 1 : √2
- D. √2 : 1
Explanation
Option B is correct.Given data: m1= 2kg, m2=4 kgh1= 60m ,h2=30mFind out: K.E1/K.E2=?Solution:According to the law of conservation of energyGain in K.E = Loss in P.EK.E = mghK.E1/K.E2= m1g(h1-h2)/m2g(h1-h2) =2*10(60-30)/4*10(60-30) =2/4 =1/2 =1:2
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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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