A car accelerates from rest with `2 m // s^(2)` on a straight line path and then comes to rest after applying brakes. Total distance travelled by the car is 100 m in 20 seconds. Then, the maximum velocity attained by the car is

Options

A. 10m/s
B. 20m/s
C. 15m/s
D. 5m/s

Answer

A

Explanation

Acceleration, `s=(1)/(2)(alphabeta)/((alpha+beta))t^3=100`
`te=20 sec, alpha =2`
`=100=(1)/(2)(2beta)/((2+beta))20xx20`
`rArr (beta)/(2+beta)=(1)/(4)`
`rArr 4beta=2+beta`
`rArr 3beta=2`
`rArr beta=(2)/(3)m//s^2`.
Maximum velocity `=(alphabeta t)/(alpha+beta)`
`=((2xx(2)/(3)xx20))/((2+(2)/(3))`
`=((80)/(3))/((8)/(3))`
`=10m//s`.