Question #1 A ball is tossed from the ground with an initial velocity of 39.2m p
ID: 2843883 • Letter: Q
Question
Question #1 A ball is tossed from the ground with an initial velocity of 39.2m per second. Find :
a) The velocity at any time, t
b) The equation for height at any time, t
c) When will the ball reach its highest point?
d) What is the maximum height?
e) How long is the ball in the air?
f) What is the acceleration of the ball at itsh highest point?
g) What is the velocity upon impact ?
h) What is the total distance traveled by the ball?
Question #2 Another ball is thrown upwards at a different time. Its initial velocity is 80 feet per second and its height at time t=1 is 70feet. Find:
a) The velocity at any time, t
b) The equation for height at any time, t
c) When will the ball reach its highest point?
d) What is the maximum height?
e) How long is the ball in the air?
f) What is the acceleration of the ball at itsh highest point?
g) What is the velocity upon impact ?
h) What is the total distance traveled by the ball?
Explanation / Answer
Taking downward direction as positive
u= -39.2 m/s
a= 9.8 m/s^2
a)
v= u + at
v(t) = -39.2 + 9.8 t
b)
height = h
displacement = -h
s= ut+ 0.5at^2
-h = -39.2 * t + 0.5 * 9.8 t^2
h= 39.2 t - 4.9 t^2
c)
at highest point
v= 0
t= u/g = 39.2 / 9.8 = 4 sec
d)
Hmax = 39.2 * 4 - 4.9 * 16
= 78.4 m
e)
Ball comes back to ground
Net displace ment = 0
0 = 39.2 t - 4.9 t ^ 2
t = 39.2/ 4.9 = 8 sec
f)
a= 9.8 m/s^2 (downward)
g)
Vimpact = Velocity after 8 sec
V = -39.2 + 9.8 * 8 = 39.2 m/s (downward)
h)
Total distance = 2 * maximum height = 2 * 78.4 = 156.8 m