This is done using the following equations of straight-line motion:
Vf = Vi + at
Where: Vf = final velocity
Vi = initial velocity
a = acceleration (in this case, gravity)
t = time
We first have to determine how long it stays in the air on the way up. Substituting the given values and solving for t:
0 = 4 + (-9.8)t
t = -4 / -9.8
t = 0.41s
Using the following equation to solve for displacement, s:
s = Vi t + 1/2 (at^2)
s = 4*0.41 + 1/2 ((-9.8)(0.41^2))
s = 0.81 m
Therefore, the displacement of the ball upwards is 0.8 meters. Among the choices, the correct answer is C.
