Question
Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take g constant with a value 10 m/s2. The work done by the (i) gravitational force and the (ii) resistive force of air is
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(i) – 10 J (ii) –8.25 J
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(i) 1.25 J (ii) –8.25 J
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(i) 100 J (ii) 8.75 J
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(i) 10 J (ii) –8.75 J
Solution
D.
(i) 10 J (ii) –8.75 J
wg+ wa= Kf– Ki
wa= –8.75 J i.e. work done due to air resistance and work done due to gravity = 10 J
