Question

A square plate of mass 120 g and edge 5.0 cm rotates about one of the edges. If it has a uniform angular acceleration of 0.2 rad/s ², what torque acts on the plate ?

Answer 1

A square plate of mass 120 gm and edge 5 cm rotates about one of the edge.
Let take a small area of the square of width dx and length a which is at a distance x from the axis of rotation.
Therefore mass of that small area
m/a² × a dx (m = mass of the square ; a = side of the plate)