Question

A body of mass m kg. Starts falling from a point 2r above the earth's surface. Its kinetic energy when it has fallen to a point r' above the earth's surface [r-radius of earth, m-mass of earth, g-gravitational constant]

Answer 1

Answer:When body starts to fall towards earth's surface, its potential energy decreases so kinetic energy increases.

Increase in kinetic energy = decrease in potential energy

Final Kinetic - Initial Kinetic Energy = Initial Potential energy - Final Potential Energy

Final - 0 = −GMmR+2R−(−GMmR+R)

Final = −GMm3R+(GMm2R)

Final = (GMm6R)

Explanation:

Answer 2

Answer:

see the attached image

Explanation:

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