Texts: A dolphin whose mass is m = 77 kg increases its speed from vi = 5.4 m/s to vf = 18.1 m/s in a time of Δt = 3.65 s while moving in a straight line. Write an expression for the magnitude of the average net force on the dolphin during the given time interval. Favg = What is the magnitude, in newtons, of the average net force on the dolphin? Fave =