1.
Please explain
14. A boy throws a ball from the ground to the top of a building. The ball just lands on the edge
of the top of the building. (4 pts) Which of the trajectories shown on the drawing would the ball
follow to the top of the building? a) + X b) (4 pts). The ball is in flight for 1.5 seconds. Just as
the boy releases the ball, what is the y component of the initial velocity of the ball? At the instant
the boy releases the ball, how does the speed of the ball compare to the y component of the initial
velocity of the ball? just in words -no calculation necessary) c) (2 pts)
Solution
(A)
the ball will follow the path ( c)
(b)
along vertical
initial velocity = voy
at teh top
final velocity vy = 0
acceleration ay = -g = -9.8 m/s^2
tiem taken t = 1.5 s

2.
vy = voy + ay*t
0 = voy - 9.8*1.5
voy = 14.7 m/s = 15 m/s
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c)
the speed of the ball = vo
vertical component = voy = vo*sintheta
voy , vo
the speed vo of the ball is always greater than the y component