A raindrop of mass `1g` falling from a height of `1km` hits is the ground with a speed of `50 ms^(-1)`. Which of the following statements is correct? `("Taking" g= 10ms^(-2))`.

Explanation

Here,`m=1.00g=10^(-3)kg,` `h=1km =10^(3)m,` `upsilon=50m//s,g=10ms^(-2)`
(a) Loss of P.E. of drop `=mgh =10^(3)(10)10^(3)=10J`
(b) Gain in K.E. of drop `=(1)/(2)m upsilon^(2)=(1)/(2)xx10^(-3)(50)^(2)=1.25J`
(c) No. This is because a part of P.E. lost is used up in doing work against the viscous drag of air.