A ceiling fan starts from rest and attains a steady angular speed of in while…

PHYSICS · Subjective · CBSE · Physics · System of Particles and Rotational Motion · System of Particles and Rotational Motion

Problem

A ceiling fan starts from rest and attains a steady angular speed of

180\,\text{rev\,min}^{-1}

20\,\text{s}

while rotating with uniform angular acceleration. It then continues to run at this constant speed for the next

40\,\text{s}

before being switched off. (a) Calculate the magnitude of its angular acceleration during the first

20\,\text{s}

. (b) Determine the total number of revolutions executed in the first

20\,\text{s}

. (c) Find the angular displacement, in radians, during the

40\,\text{s}

of steady running. (d) Hence calculate the total number of revolutions made by the fan in the entire

60\,\text{s}

interval considered. Show each step of your working clearly.