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 $5 \mathrm{~m} / \mathrm{s}$. The work done by the unknown resistive force is ______ J. (take $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^{2}$)

JEE Main · 2026 · 06 Apr 2026 · Shift 1 · Work, Power & Energy

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}

)

(A)-8.75
(B)-8.35
(C)-9.55
(D)-9.98✓ Correct

Answer: (D)

Solution

By the work–energy theorem the total work equals the change in kinetic energy:

W_{g r a v} + W_{r es} = \frac{1}{2} m v^{2}

. Gravity does

W_{g r a v} = m g h = 1 0^{- 3} \times 10 \times 1000 = 10

J over the fall. Hence

W_{r es} = \frac{1}{2} m v^{2} - m g h = \frac{1}{2} \times 1 0^{- 3} \times 5^{2} - 10 = 0.0125 - 10

. The work done by the resistive force is

- 9.98

JEE Main · 2026 · 06 Apr 2026 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Work, Power & Energy →

More JEE Main questions on Work, Power & Energy

Given below are two statements:
Statement I: An object moves from position $r_{1}$ to position $r_{2}$ under a conservative force field $F$ . The work done by the force is $W = - \int_{r_{1}}^{r_{2}} F \cdot d r$ .
Statement II: Any object moving from one l …
JEE Main 2026View solution →
Consider two identical metallic spheres of radius $R$ each having charge $Q$ and mass $m$ . Their centers have an initial separation of $4 R$ . Both the spheres are given an initial speed of $u$ towards each other. The minimum value of $u$ , so that they can just touch e …
JEE Main 2026View solution →
A body of mass 2 kg is moving along x-direction such that its displacement as function of time is given by $x (t) = α t^{2} + β t + γ m$ , where $α = 1 m / s^{2}$ , $β = 1 m / s$ an …
JEE Main 2026View solution →
In case of vertical circular motion of a particle by a thread of length r if the tension in the thread is zero at an angle 30° shown in figure, the velocity at the bottom point (A) of the circular path is (g = gravitational acceleration)
JEE Main 2026View solution →
A spherical ball of mass 2 kg falls from a height of 10 m and is brought to rest after penetrating 10 cm into sand. The average force exerted by sand on the ball is $____$ N.
JEE Main 2026View solution →
A 1 kg block subjected to two simultaneous forces $(2 \hat{i} + 3 \hat{j} + 4 \hat{k})$ N and $(3 \hat{i} - \hat{j} - 2 \hat{k})$ N is moved a distance of 25 m along $(3 \hat{i} - 4 \hat{j})$ direction. The work done in this process is _____ J.
JEE Main 2026View solution →