IOM 2017, Блиц — Задача 76

OLYMPIAD OF METROPOLISES. Moscow, September 4 · 4 септември 2017 г.

Условие

A brick of a mass of 2.0 kg lies on top of a bigger one of 4.0 kg. The coefficient of static friction between the horizontal surface and the bigger brick is μ1=0.10\mu_1 = 0.10 and the coefficient of static friction between the two bricks is μ2=0.30\mu_2 = 0.30. Figure out the maximum force to pull the pile of bricks without shifting the upper one. The force is applied at the point of no torque, i.e. where all force moments add to zero.

A 2 kg brick on top of a 4 kg brick resting on a horizontal floor; μ2 = 0.3 between the bricks, μ1 = 0.1 between the lower brick and the floor; a red arrow pulls the lower brick to the right, labelled Fmax = ?

The answer should be given in the SI units unless otherwise stated. If the numerical result turns out to be an integer, it should be given as the answer. Otherwise round the result to the first decimal.
g=10 m/s2g = 10\ \mathrm{m/s^2}.

Отговори

Решение

Оригинал в Архива: blitz.pdf · официални решения: answers-blitz.pdf