The 750,000-lb jetliner A has four engines, each of which produces a nearly constant thrust of 40,000

Question:

The 750,000-lb jetliner A has four engines, each of which produces a nearly constant thrust of 40,000 lb during the takeoff roll. A small commuter aircraft B taxis toward the end of the runway at a constant speed v_B = 15 mi / hr. Determine the velocity and acceleration which A appears to have relative to an observer in B 10 seconds after A begins its takeoff roll. Neglect air and rolling resistance.