Question

A phonograph record rotates at 45 revolutions/minute. (a) What is its angular speed in rad/s? (b) Through how many degrees does it rotate in 0.2 s?

Answer 1

Dear student
$$\begin{gathered} a)angulardisplacementinonerevolution=2\pi \\ soangularvelocity=45revolutoin/minute=45\times 2\pi /60=1.5\pi rad/s \\ and \\ b)angulardisplacementin.2s=1.5\pi \times .2=.3\pi rad \\ rotationindegree=.3\times \pi 180/\pi ={54}^0 \end{gathered}$$
Regard

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