# physical

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A boy throws a stone vertically up to a man standing at a heigt of 2 m above the boy. Of the stone is thrown up with a velocity of 7.0m s what is the velocity of the stone at the instant when it is caught by the man.

A clear explaination is greatly appreciated

• physical science -

Kinetic energy of M*g*H is lost, with H = 2.0 m.
The initial Velocity is
V1 = 7.0 m/s

The final kinetic energy is

(1/2) M V2^2 = (1/2) M V1^2 - M g H

Cancel out the M's and solve for the final velocity V2.
V2^2 - V1^2 = -2 g H

• physical -

Does that give me a negative velocity?

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