Answer:
t = 9.08 sec
Explanation :
This requires the use of the kinematic equations.
u = initial velocity = 21.8 m/s
v = final velocity = 0
t = time = what we're trying to find.
So we use the equation that relates d, u, v and t. This is
d = distance = 99m
d = [tex]\frac{t*(u+v)}{2}[/tex]
and since v = 0 this reduces to d = [tex]\frac{tu}{2}[/tex]
which rearranges to t = [tex]\frac{2d}{u}[/tex]
t = [tex]\frac{2*99}{21.8}[/tex] =9.08 seconds
t = 9.08 sec