11. It's the middle of the night and you randomly see a man push an unknown object across an unknown surface. He pushes with a force of 300. N causing the object to move at constant velocity. If the mass
of the object is 225. kilogram, what is the coefficient of friction between the object and the surface?
A) 0.136
B) 0.164
C) 0.536
D) 0.255

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.