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Question # 40
A body falls freely under gravity. If speeds is v when it has lost an amount x of the gravitational P.E, then its mass is:

2x / v2
2x / v3
2x / v4
none
please give me its solution

Respuesta :

Answer:

Potential Energy = x = m g h

Kinetic energy = 1/2 m v^2

Assuming the mass fall from rest

1/2 m v^2 = m g h

v^2 = 2 g h

So the speed attained is independent of the mass

Also, x / v   does not have the units of mass

So the solution is none of the above.

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