Motion in a Plane
Class 11 · Motion in a Plane
Rain–Man Problem
Walker in vertical rain — compute umbrella tilt angle.
Key Notes
01
Rain falls vertically with speed v_r. Man walks with speed v_m horizontally.
02
Rain relative to man: v_rain/man = v_rain − v_man.
03
Umbrella tilt angle (from vertical) = tan⁻¹(v_m/v_r).
04
Speed of rain relative to man: √(v_r² + v_m²).
Formulas
Umbrella angle
Angle from vertical, toward the direction of motion.
Important Points
The faster you walk, the more you tilt the umbrella — up to nearly horizontal.
Rain–Man Problem notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 11 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.