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It is well known that a raindrop falls u...

It is well known that a raindrop falls under the influence of the downward gravitational force and the opposing resistive force. The latter is known to be proportional to the speed of the drop but is otherwise undetermined. Consider a drop of mass `1.00g` falling from a height `1.00km`. It hits the ground with a speed of `50.0 ms^(-1)`.
What is the work done by the gravitational force?

Text Solution

Verified by Experts

The change in kinetic energy of the drop is
`triangleK= (1)/(2)mv^(2)-0`
`=(1)/(2)xx10^(-3)xx50xx50 = 1.25 J`
where we have assumed that the drop is initially at rest.
Assuming that g is a constant with a value `10 m"/"s^(2)`, the work done by the gravitational force is,
`W_(g)= mgh`
`=10^(-3)xx10xx10^(3)= 10.0 J`.
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