a rounded object with 2 kg mass and 10 cm radius is released from rest at the top of 14 m tall incline with a 30o angle, and coefficients of friction . a) at the bottom of the incline the linear speed is 14 m/s. is the object a solid sphere, a disc, or a spherical shell? b) suppose we increase the angle of the incline above 30o. at what angle will the object start to slide instead of roll?