A ball is dropped from a building of height 45 m. Simultaneously another ball is thrown up with a speed 40 m/s. Calculate the relative speed of the balls as a function of time.
According to the problem, for the ball dropped from the building, u1=0 and u2=40m/s Velocity of the ball after time t, v1=u1−gt v1=−gt And for another ball which is thrown upward, u2=40m/s Velocity of the ball after time t, v2=u2−gt=(40−gt) Therefore, Relative velocity of one ball with respect to another ball is, v12=v1−v2=−gt−[−40−gt] v12=v1−v2=−gt+40+gt=40m/s