If a trapeze artist rotates once each second while sailing through the air, and contracts to reduce her rotati

Question

If a trapeze artist rotates once each second while sailing through the air, and contracts to reduce her rotational inertia to one fifth of what it was, how many rotations per second will result?

Answer 1

The answer is: 5 rotations per second.

By "rotational inertia" you mean what is more commonly called the trapeze artist's "Moment of Inertia." Let's call that MI.

Angular momentum is (MI)w, where ' w ' is the angular velocity. The principle in this problem is that angular momentum is conserved, unless some new torque acts on the rotating body.

So, if (MI)w is conserved, and MI DECREASES by a factor of 5, then w must INCREASE by a factor of 5.

Live long and prosper.

Answer 2

Answer is : the artist will rotate 3 times per second. By the conversation of angular momentum , the artist will increase rotation rate by 3 .