Question

the velocity V of a body moving along a straight line varies with time T as V = 2t^2e^-t, , where v is in m/s and t is in second . the acceleration of body is zero at t = (1) 0 (2) 2 s (3) 3 s (4) both (1) & (2)

Answer 1

acc=e^-t(4t-2t^2). is 0 for t=0 and=2. ans (4)