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When you drop a pebble from height H, it reaches the ground with speed V if there is no air resistance. From what height should you drop it so it will reach the ground with twice speed?

Respuesta :

MechEngineer

Answer:

H quadrupled

Explanation:

Since we are neglecting air resistant, gravitational acceleration g is the only thing that affect the pebble:

As v = gt. To get twice the speed 2v with the same acceleration g, the time must be doubled.

Yet to get to distance H with 2t time. Since [tex]H = gt^2/2[/tex]. If t is doubled, H must be [tex]2^2 = 4[/tex] times the original amount.

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