Math question distance

Question

A handbag is dropped from the top of Centre Point Tower. The distance s travelled after t seconds is given by the formula s=4.9t². For this falling handbag, find the instantaneous velocity at t=4 seconds.

Answer 1

Hint: s is a distance function. What you want to find is the function of velocity which is derivative of s. So find ds at t = 4.

Answer: s(t) = 4.9t²

=> v(t) = ds = 4.9*2*t

=> v(4) = 4.9*2*4 = 39.2

Answer 2

Evaluate the function at t=4 and t=4.1 and subtract the smaller from the larger.