posted by Fatima .
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.
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