A particle moves along a straight line with equation of motion
s = f(t) where s is measured in meters and t in seconds. Find the velocity and the speed when t = 4.
f(t) = 15 + 40t + 1
it said that t= 4 and because the t is after the 40 you would times 40 by 4 to get 160. Then you add them all up and there you go you got your velocity and speed.