An object starting from rest travels `20 m` in first `2 s` and `160 m` in next `4 s`. What will be the velocity after `7s` from the start.

Explanation

Given , object starts from rest, u = 0,t = 2s and s = 20m
From second equation of motion ,s = `ut + 1/2at^(2)`
On putting u - 0 in above equation , 20 = `0 xx2 +1/2xxa (2)^(2) = 0 +1/2 xx a xx 4`
`20 = 2a rArr a=20/2 rArr a = 10m//s^(2)`
Now, from first equation of motion, velocity after 7 s from the start
v = u + at `[put a = 10m//s^(2)]`
= 0 `+10xx7 = 70 m//s`