Answer:
1.13 s
Step-by-step explanation:
We can assume that the motion of the rider is a uniformly accelerated motion, therefore we can solve the problem by using the following suvat equation:

where
s is the displacement
u is the initial velocity
v is the final velocity
t is the time
In this problem,
s = +14.7 m
u = +8 m/s
v = +18 m/s
Solving the formula for t, we find:
