Question

A body moving along x–axis is at x = –5 m at t = 0. It covers 10 m is the third second and 28 m in the sixth second. The position of this body at t = 8 s is

(1) 192 m

(2) 152 m

(3) 147

(4) 40 m

Answer 1

(3) 147

Given,

x₀ = -5m . The distance s₃ travelled in third second is

Similarly the distance travelled in 6^th second; s₆ , is

From Eqns. (1) and (2) we have

18 = 3a or a = 6 ms^-2

From Eqn (1), we get

At t = 8 s, the position x₈ of particle is