A boy is trying to roll a bowing ball up a hill as shown in the image below. If friction is ignored what is the minimum initial velocity that the ball must have for it to reach the top of the hill? (Recall that g=9.8 m/s^2)
A.14 m/s
B.21 m/s
C.28 m/s
D.7 m/s

16. a brave but inadequate rugby player is being pushed backward by an opposing player who is exerting a force of 800 n on him. the mass of the losing player plus equipment is 90.0 kg, and he is accelerating at 1.20m/s2 size 12{1 "." "20"" m/s" rsup { size 8{2} } } {} backward. (a) what is the force of friction between the losing player’s feet and the grass? (b) what force does the winning player exert on the ground to move forward if his mass plus equipment is 110 kg? (c) draw a sketch of the situation showing the system of interest used to solve each part. for this situation, draw a free-body diagram and write the net force equation.