Question

S=t³-6t² find the acceleration when the body is at rest

Answer 1

Answer:

Explanation:V = ds/dt = d(t3 - 6t2)/dt = 3t2 - 12t —— (1)

a = dV/dt = d(3t2 - 12t)/dt = 6t - 12 —— (2)

For body at rest, V = 0. Using (1), we get:

3t2 - 12t = 0 or, 3t(t-4) = 0.

Thus, two different times t = 0 and t = 4 correspond to solution. Solving for acceleration, using (2), we get :

At t = 0, a = 6*0 - 12 = -12

At t = 4, a = 6*4 - 12 = 12

QED