⚛️ Physics · Motion in a Plane · NEET & JEE

Rain falls vertically at 10 m s^-1. A man runs horizontally at 10 m s^-1. To keep dry he should tilt his umbrella from the vertical by:

Answer: 45°.

A 60°
B 30°
C 45°
D 90°

Correct answer: C. 45°

Explanation: In the man's frame the rain appears to come at tanθ = v(man)/v(rain) = 10/10 = 1, so θ = 45° from the vertical.

Projectile trajectories launched at 15, 30, 45, 60, 75 and 90 degrees at the same speed, each annotated with range R, maximum height H and time of flight T, with coloured dots marking equal time intervals

Projectiles at equal speed: range is maximum at 45°, and complementary angles (30° and 60°) share the same range. Image: Cmglee, CC BY-SA 3.0, via Wikimedia Commons.

Concept context

Vectors, projectile motion, uniform circular motion, and relative velocity - the foundation of 2D kinematics for NEET and JEE.

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Rain falls vertically at 10 m s-1. A man runs horizontally at 10 m s-1. To keep dry he should tilt his umbrella from the vertical by:

Concept context

More Motion in a Plane questions

Rain falls vertically at 10 m s^-1. A man runs horizontally at 10 m s^-1. To keep dry he should tilt his umbrella from the vertical by: