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Studentka2010 [4]
3 years ago
15

A key falls from a bridge that is 44 m above the water. It falls directly into a model boat, moving with constant velocity, that

is 19 m from the point of impact when the key is released. What is the speed of the boat
Physics
1 answer:
Lady_Fox [76]3 years ago
6 0

The time t it takes for the key to fall 44 m is

44\,\mathrm m=\dfrac12\left(9.8\,\dfrac{\mathrm m}{\mathrm s^2}\right)t^2\implies t=3.0\,\mathrm s

(notice I'm taking the downward direction to be positive)

The boat, moving at a presumably constant speed, then has 3.0 s to travel 19 m to the point of impact, which means its speed must be

v=\dfrac{19\,\mathrm m}{3.0\,\mathrm s}=6.3\,\dfrac{\mathrm m}{\mathrm s}

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