The rain drop of mass 1 g, starts with zero velocity from a height of 1 km

Question

The rain drop of mass 1 g, starts with zero velocity from a height of 1 km. It hits the ground with a speed of 5 m/s. The work done by the unknown resistive force is _____ J. (Take g = 10 $m / s^{2}$ ) [2026]

Smart Achievers · Accepted Answer

(4)

$W_{F} + W_{g} = Δ K$

$W_{F} + m g h = \frac{1}{2} m v^{2} - 0$

$W_{F} + 1 \times 10^{- 3} \times 10 \times 10^{3} = \frac{1}{2} \times 10^{- 3} \times 25$

$W_{F} = - 9.98 J$

Solution

Q.
The rain drop of mass 1 g, starts with zero velocity from a height of 1 km. It hits the ground with a speed of 5 m/s. The work done by the unknown resistive force is _____ J. (Take g = 10 $m / s^{2}$ ) [2026]

1 - 8.75

2 - 8.35

3 - 9.55

4 - 9.98

Ans.
(4)

$W_{F} + W_{g} = Δ K$

$W_{F} + m g h = \frac{1}{2} m v^{2} - 0$

$W_{F} + 1 \times 10^{- 3} \times 10 \times 10^{3} = \frac{1}{2} \times 10^{- 3} \times 25$

$W_{F} = - 9.98 J$

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