Circular motion Question

Question

Kangaroo Jack is trying to catch a crane with a bola. The mass on the end of the bola is 250g and the bola makes 3 revolutions every 2 seconds with a velocity of 11 m/s. How long is the bola?

Answer 1

For 3 revs in 2 seconds, the period of revolution T is 2/3 s/rev. In circular motion the speed is circumference/period, 11 = 2πr/T, or length r = (11 T) / (2π) = (22/3) / 6.28... = 1.17 m. (The mass doesn't factor into this).