0.0 A 30-kg ball is sitting on top of a 50 m hill. The ball rolls down the hill. As the ball reaches the very bottom of the hill, what is its
velocity? (Assuming no energy is lost due to friction. This would mean that the PEtop = KEbottom)

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.