Question

A particle moving with a non-zero velocity & constant acceleration on straight line travels 15 m in first 3 s & 33 m in next 3 s in the same direction,find
(i) initial velocity of particle
(ii) acceleration of particle

Answer 1

The particle travels a distance of 15 m in the first 3 s.
s₁ = u₁t+0.5at²
15 = 3u₁+4.5a ...(1)
The particle travels a distance of 33 m in the second 3 s.
s₂ = u₂t+0.5at²
u₂ = u₁+at = u₁ +3a
s₂=33 = (u₁+3a)3+4.5a = 9a+3u₁+4.5a
33=9a +(3u₁+4.5a) = 9a + 15
⇒33-15 = 9a
⇒18 = 9a
Hence, a = 2 m/s²
Putting the value of a in eq. (1), we get
15 = 3u₁ +4.5×2
⇒3u₁ = 15-9
⇒u₁ = 6/3 = 2 m/s