JEE Main · 2021 · 31 Aug 2021 · Shift 1 · Kinematics

A helicopter is flying horizontally with a speed '

v

' at an altitude '

h

' has to drop a food packet for a man on the ground. What is the distance of helicopter from the man when the food packet is dropped?

(A) $2 g h v^{2} + h^{2}$
(B) $\frac{2 v ^{2} h}{g} + h^{2}$ ✓ Correct
(C) $\frac{2 g h}{v ^{2}} + h^{2}$
(D) $\frac{2 g hv ^{2} + 1}{h ^{2}}$

Answer: (B)

Solution

The packet falls through height

h

in time

t = \frac{2 h}{g}

, during which it covers a horizontal distance

x = v t = v \frac{2 h}{g}

. At the instant of release the straight-line distance from the helicopter to the man is

d = x^{2} + h^{2} = \frac{2 v ^{2} h}{g} + h^{2} .

JEE Main · 2021 · 31 Aug 2021 · Shift 1 · Single correct option

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