Question

a body moves in a straight line with initial velocity and uniform acceleration.find how far it travels in12s,given that it travel 246m in the 1st 6seconds,and 69m in the last 3seconds.find also the initial velocity.

Answer 1

V = Vo + a t
X = Vo*t + (a/2) t^2 (distance travelled at time t)
Vo is the initial velocity and a is the acceleration.

Velocity at t = 10.5 s = 69/3 = 23 m/s
Velocity at t = 3 s = 246/6 = 41 m/s
Acceleration = (23 - 41)/7.5 = -2.4 m/s^2

41 = Vo + 3a = Vo - 7.2
Vo = 48.2 m/s

Total distance travelled at t = 12 s
= 48.2*12 - 1.2*144 = 405.6 m

Answer 2

thanks alot