Question 235: Laws of Motion

Question

A stone is dropped from a height h. It hits the ground with a certain momentum P. If the same stone is dropped from a height 100% more than the previous height, the  momentum when it hits the ground will change by

Accepted Answer

When a stone is dropped from a height h,
it hits the ground with a momentum
$$P = m\sqrt {2gh} $$     ....(1)
where m is the mass of the stone.
When the same stone is dropped from a height 2h
(i.e. 100% of initial), then its momentum with which
it hits the ground becomes
$$P' = m\sqrt {2g\left( {2h} ight)}  = \sqrt 2 P$$      [Using (1)]     ...(2)
% change in momentum = $${{P' - P} \over P} 	imes 100\% $$
$$ = {{\sqrt 2 P - P} \over P} 	imes 100\%  = 41\% $$

Answer

68%

Answer

41%

Answer

200%

Answer

100%

Laws of Motion

A stone is dropped from a height h. It hits the ground with a certain momentum P. If the same stone is dropped from a height 100% more than the previous height, the momentum when it hits the ground will change by

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