A student is whirling a stopper about her head horizontally. the mass of thr stopper is .1kg and takes 3.14 seconds to make one revolution. the radius is 2 meters. what is the speed of the stopper?

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.