<p>And now I think that part c of #2 is wrong as well, using conservation of energy:
U = K + Work done by friction. I get 5.29 m/s without considering the rotational energy (damn why couldn’t have I thought of this during test):, but considering the rotational energy I am getting v equals 4.48 m/s. Just to show my work:</p>
<p>mgh = .5mv^2 + .5(.4)mv^2 + 8.4*4 (work done by friction), when you do all those computations you get v = 4.48 m/s. I don’t know how you guys got your answers but were you taking into account the speed of rotation of the ball?</p>