Answer:
Time, t = 5 seconds
Step-by-step explanation:
It is given that,
Initial speed of the bike, u = 8 m/s
Final speed of the bike, v = 14 m/s
Length of the hill, d = 55 m
Firstly, we can find the acceleration of the bike. Let it is equal to a. It can be calculated using third equation of motion as :
![a=(v^2-u^2)/(2d)](https://img.qammunity.org/2020/formulas/physics/college/pwtn847zxmna9ip01ny79oob4wz2kuprf0.png)
![a=1.2\ m/s^2](https://img.qammunity.org/2020/formulas/physics/middle-school/6ksms0563vhr732g7hpi9ddudmgfpodms7.png)
Let t is the time passes during the descent. It can be calculated using the first equation of motion as :
![t=(v-u)/(a)](https://img.qammunity.org/2020/formulas/physics/college/x99fd00llnhqqwna9ostz55ku5q1qgcrew.png)
t = 5 seconds
So, the time passes during the descent is 5 seconds. Hence, this is the required solution.