Let two persons ride parallel to each other in the same direction starting together from the same station with the same velocity u. Then the relative velocity of one person with respect to the other is zero. Again suppose they are going in the same direction with different velocities. say one is going at the rate of 10 km/h and the other at the rate of 15 km/h. Then the relative velocity of one with respect to other is 5 km/h. Again suppose they are going in opposite directions. Then the relative velocity of one relative to the other is 25 km/h.

Thus, in all the above cases the relative velocity of one with respect to the other is obtained

by compounding the true velocity of one with a velocity equal and opposite to the other. Hence we arrive at the following definitions.
When the distance between the two points is changing either in magnitude or in direction or in both, each point is said to have a relative velocity with respect to the other. Also the relative velocity of one point B with respect to a second point A is obtained by compounding with the velocity of B, a velocity which is equal and opposite to that of A.
A. The distance s in metres travelled by a particle in t seconds is given by s = a * e ^ t + b * e ^ (- t) Show that the acceleration of the particle at time t is equal to the distance travelled by it in time f.
B.A particle is moving in a straight line such that its distance in centimetres from a fixed point after 1 seconds is given by s=2t^ 3 +3t+5. Find the velocity, acceleration and the distance travelled at the end of 3 sec.
please answer only part B.