Question

How much energy is require to set a 0.304m phonograph record into rotation at 33.33 revolution per minute if the mass of the record is 0.11kg?

Answer 1

The mass of the turntable is not trivial, and probably more important for motor and drive design. However,

Thin disk moment of inertia= 1/2 m r^2

rotational energy gained= 1/2 I w^2

w=33.3*2PI*60

energy total= 1/2 (m *.304^2)(33.3*2PI*60)^2

you know m, and PI, compute in joules