Question

A man is walking due west at 5 kmph. Rain appears to him to be falling vertically downwards at the rate of 5 kmph. Then true velocity of the rain fall is
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Answer 1

Velocity of rain with respect to the ground is 5√2 km /hr

Given-

• Speed of man due west  = 5 kmph

• Rain falling vertically downwards with a speed of = 5 kmph

• Velocity of man with respect to ground is (Vmg) = 5 (-i) kmph
• Velocity of rain with respect to man (Vrm) = 5 (-j) kmph

Vrm = Vrg - Vmg

- 5 (j) = Vrg - (-5) (i)

Vrg = -5 j - 5 i

Magnitude of Vrg = { (-5)² + (-5)² }^1/2

Vrg = 5√2 km /hr