during the takeoff roll, a boeing 747 jumbo jet is accelarating at 4m\s. it requires 40 s to reach takeoff speed. what is the initial velocity of the jet?

Answer 1

V2 = a*t = 4 * 40 = 160 m/s = Take-off speed.
V2 = V1 + a*t.
160 = V1 + 4*40, V1 = 0.