A light horizontal rod long is attached to a wall by a frictionless pivot at its left end

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A light horizontal rod

2.0\,\text{m}

long is attached to a wall by a frictionless pivot at its left end. Two downward forces act on the rod:

30\,\text{N}

at a point

0.50\,\text{m}

from the pivot and

20\,\text{N}

at a point

1.5\,\text{m}

from the pivot. To keep the rod in rotational equilibrium, an upward vertical force

F

must be applied at the right end. What is the magnitude of

F

? (a)

27.5\,\text{N}

(b)

45\,\text{N}

(c)

22.5\,\text{N}

(d)

15\,\text{N}