A body `A` starts from rest with an acceleration `a_1`. After `2` seconds, another body `B` starts from rest with an acceleration `a_2`. If they travel equal distances in the `5^(th)` second, after the start of `A`, then the ratio `a_1 : a_2` is equal to :

Options

A. `5:9`
B. `5:7`
C. `9:5`
D. `9:7`

Answer

A

Explanation

`A`: `s=0+1/2a_(1)(2xx5-1)=(9a_(1))/2`
`B: s=0+1/2a_(2)(2xx3-1)=(5a_(2))/2`
`(9a_(1))/2=(5a_(2))/2impliesa_(1)/a_(2)=5/9`