18. In an airplane flying at a constant speed, the
force pushing the airplane forward is exerted
by the engine and is equal to the opposite
force of air resistance. Describe how these
forces compare when the plane speeds up
and slows down. In which direction is the
net force on the airplane in each case?
In an airplane flying a constant speed, the force exerted by the engines pushing the plane forward is equal to the opposite force exerted by air resistance.