Question

2) Two solid rubber balls (one of mass m and radius r, and the other of mass M and radius R) roll without slipping up an incline. They are, initially, moving at 7.0 m/s. Eventually, they stop for a split second and then start to fall back down. Which ball goes higher? (15 points. Hint: find KE and Rotational KE for both). Calculate the height that each will reach (5 points). Hint: Use conservation of total mechanical energy). The moment of Inertia of a solid ball is 1 (2/5) mr? 3) A water balloon is tossed out of the window of a student's dorm room. It is launched horizontally off the edge and hits another student located 9.0 m away from the bottom of the dorm smack dab on the head. The window is 9.0 m higher than the student's head. a) How long does it take for the balloon to hit the intended victim (10 points)? What the water balloon's velocity (magnitude and direction) when it hits (10 points)?

Answer 1

02 5 2 R2 By conservation of Energy Mgh-1 Mv+ I w? v=Rw = w = I = 3 MR? Mgh=IMV2 + 1 X 2 MR² x y z gh= y2 + y² Th= 7,27 - As height does not I log depend on mass 2 radius so both will reach same height 03 (0) 2=3m, using h= gt? 3= 1x8.8th Itime taken = 0.78 sec) (6) Velocity in a direction Ved = 11.51m/s. Vy=gt = 9.8+0.78 = 7:644 m/s TU-detyr – 13.82 m/s) Magnitude. Angle = 33.59° below horizontal 0.78