Question

A majorette in a parade is performing some acrobatic twirlings of her baton. Assume that the baton is a uniform rod of mass 0.120 kg and length 80.0 cm .

a) Initially, the baton is spinning about a line through its center at angular velocity 3.00 rad/s . (Figure 1)

What is its angular momentum? Express your answer in kilogram meters squared per second.

Answer 1

ml 12 0.12x0.80 Moment of inertia of the rod I- 12 -6.4x10 kgm Angular momentum L -Ic 6.4x10 x3 -0.0192 kgm/s

Answer 2

The magnitude of angular momentum equals L = I x w,

where w = angular frequency (the magnitude of angular velocity) and

I = moment of inertia for the long uniform rod rotating around the axis through center =1/12 m x L²,

therefore,

L=I x w,

putting the values:

L = 1/12 x 0.120 kg x (0.800 m)² x 3.00 rad/s = 0.0192 kg m²/s

thus, angular momentum is 0.0192 kg m²/s