Question

A bike that is coasting down a steep hill increases its speed from 8.0 m/s to 14 m/s. The length of the hill is 55 meters. How much time passes during the descent?

Answer 1

t=5s

it was correct on my do-now

so I hope it was useful for you

Answer 2

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)`

`a=((14)^2-(8)^2)/(2* 55)`

`a=1.2\ m/s^2`

Let t is the time passes during the descent. It can be calculated using the first equation of motion as :

`t=(v-u)/(a)`

`t=(14-8)/(1.2)`

t = 5 seconds

So, the time passes during the descent is 5 seconds. Hence, this is the required solution.