IOM 2019, Блиц — Задача 72

OLYMPIAD OF METROPOLISES, Moscow, September 2, 2019 · 2 септември 2019 г.

Условие

A fine beam of light is incident on a plane mirror at QQ. The reflected beam strikes on a screen and a light spot appears on it. The mirror is rotated in clockwise direction about QQ at a constant angular speed ω\omega. At the instant shown, θ=60∘\theta = 60^{\circ} and the mirror surface is just parallel to the screen. The light spot is at PP, where PQ=0.5PQ = 0.5 m. At this instant, the spot appears to move across the screen at a speed of 3.0 m/s. Find ω\omega.

An incident ray hits a horizontal plane mirror at Q at angle θ to the dashed normal; the reflected ray goes up to a horizontal screen, meeting it at P, with an arrow v along the screen; a curved arrow ω about Q shows the rotation.

Решение

Внимание: Непълно решение

В архива няма официално решение на тази задача.

Оригинал в Архива: blitz-en-all-task-final.pdf