An airplane has 1.50x10³ m to accelerate to a speed of 62.0 m/s to take off. If it experiences 15,000N of friction, calculate the thrust of the engines. d=1.50x10³ m vi=0 m/s vf=62.0 m/s Ff=15,000N v²=u²+2ad 62²=0+2(1.50x10³)a a=1.2813 m/s² I think I'm supposed to find the applied force, but I don't know what to do next since I can't find the mass of the airplane. A 4.5kg axe comes to a stop in a tree from 25 m/s. How much force did the tree exert on the axe? I couldn't come up with anything for this one: u=25 m/s v=0 m/s m=4.5 kg ANY HELP IS MUCH APPRECIATED!