1. The problem statement, all variables and given/known data A 1600 kg jet engine is fastened to the fuselage of a passenger jet by just three bolts (this is the usual practice). Assume that each bolt supports one-third of the load. (a) Calculate the force on each bolt as the plane waits in line for clearance to take off. (b) During flight, the plane encounters turbulence, which suddenly imparts an upward vertical acceleration of 2.0 m/s2 to the plane. Calculate the force on each bolt now. 2. Relevant equations F= ma 3. The attempt at a solution I got the correct solutions for both (a) and (b) (a) F=ma= (1600 kg)(9.8 m/s^2) = 15680 N/3= 5226.67 N (b) F=ma= (1600 kg)(9.8 m/s^2 + 2.0 m/s^2) = 18880 N/3 = 6293.33 N But on (b), I don't understand why the acceleration of gravity was added to the upward vertical acceleration of 2.0 m/s^2, isn't gravity pulling the plane down, and the 2.0 m/s^2 pulling it up, shouldn't it be 9.8-2.0?