The time variation of the position of a particle in rectilinear motion is given by x=2t3+t2+2t. If v is the velocity and a the acceleration of the particle in consistent units, the motion started with
A particle starts its motion from point A in the positive x direction in such a way that after every t sec it is at a distance of t2 from the starting point. Find its instantaneous velocity at t=4th sec also the rate at which velocity changes.