Question

A phonograph turn table rotates at 50 rev/ min . Its angular speed in rad/sec is ? a) 8.164 rad.sec-1 b) 5.23 rad.sec-1 c) 52.3 rad.sec-1 d) 81.64 rad.sec-1

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Answer 1

$\bold\red{\underline{\boxed{\sf{GIVEN : }}}}$

•A phonograph turntable rotates at 50 rev/ min.

$\bold\purple{\underline{\boxed{\sf{TO \: FIND : }}}}$

•We need to find the angular speed of the phonograph in rad/s.

$\bold\green{\underline{\boxed{\sf{SOLUTION :}}}}$

$\implies$We know the following conversions,

$\implies$1 revolution = 6.28 radian

$\implies$1 minute = 60 seconds

Therefore,

$\implies$50 × rev/min

$\implies$50 × 6.28rad/60s

$\implies$ ${\boxed{\red{\underline{\sf{5.28rad/s}}}}}$

The angular speed of the phonograph is 5.28rad/s.