Question

a particle moving in a straight line under constant acceleration. It travels 15m in 3rd second and 31m in 7th second. Find the initial velocity and constant acceleration.​

Answer 1

Answer:

Intial v = 5 m/s

Acceleration = 4 m/s²

Explanation:

W.K.T : Sn = u + a(2n-1)/2

S3 = 15, n = 3 ;

15 = u + 5a/2 ----(1)

S7 = 31, n = 7

31 = u + 13a/2 ----(2)

(2)-(1) » 16 = a(13-5)/2

32 = a(8)

a = 4 m/s²

Substitute a = 4 m/s² in any one equation:

15 = u + 5(4)/2

u = 15 - 10

u = 5 m/s

Good day :)