A Skater Who's Spinning and Torque?

Question

A skater is initially spinning at a rate of 17.9 rad/s with a rotational inertia of 2.85 kgm2 when her arms are extended. What is her angular velocity after she pulls her arms in and reduces her rotational inertia to 1.58 kgm2?

_____rad/sec

Answer 1

The I1*w1=I2*w2
or
2.85*17.9=1.58*w2

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Answer 2

hi
i will help u in this problem....

dont get confused with rotational inertia its same as angular momentum.........k

this problem uses the simple fundaa of
CONSERVATION OF ANGULAR MOMENTUM

by this,
we can say that...

L1 * W1 = L2 * W2

HERE ,
L1,L2 are the final and initial angular momentum
W1,W2 are the initial and final angular velocities...........

so by the given data

17.9 * 2.85 = 1.58 * W2
W2=32.28 rad/sec

so the angular velocity after she pulls her arms in and reduces her rotational inertia to 1.58 kgm2 is W2 = 32.28 radians per second

answer 32.28 rad/sec

hope this is the best answer uve got,
all the best