#### Question

A ballet dancer spins about a vertical axis at 2.5Π rad/s with his both arms outstretched. With the arms folded, the moment of inertia about the same axis of rotation changes by 25%. Calculate the new speed of rotation in r.p.m.

#### Solution

ω_{1} = 2.5 π rad/s = 2πn_{1}

∴ `I_2 = 3/4 I_1,n_2 (r.p.m) = ?`

By conservation of angular momentum,

I_{2}ω_{2} = I_{1}ω_{1} or I_{2} (2πn_{2}) = I_{1} (2πn_{1})

The new speed of rotation in r.p.m is 100 r.p.m

Is there an error in this question or solution?

#### APPEARS IN

Solution A Ballet Dancer Spins About a Vertical Axis at 2.5\u0001 Rad/S with His Both Arms Outstretched. with the Arms Folded, the Moment of Inertia About the Same Axis of Rotation Changes by 25%. Calculate the New Speed of Rotation in R.P.M Concept: Physical Significance of M.I (Moment of Inertia).