The velocity of a particle moving with constant acceleration at an instant `t_(0)` is `10m//s` After 5 seconds of that instant the velocity of the particle is 20m/s. The velocity at 3 second before `t_(0)` is:-

Options

A. 2 m/s
B. 3 m/s
C. 4 m/s
D. 5 m/s

Answer

C

Explanation

Using v = u + at
According to the given problems
`10 = u + at " "...(i)`
`20 = u + a(t +5) " "...(ii)`
`v = u + a(t-3) " "...(iii) `
From equations (i) and (ii) , we get `a = 2 m//s^(2)`
Substituting equation (i) and `a = 2m//s^(2)` in equation (iii) , we get
`v =10 -3 xx 2 = 4m//s`