From studying airplanes, we know that there are 4 principle forces that act on an airplane to make it fly: thrust, drag, lift and gravity.
(we; know; that there are 4 principle forces that act on an airplane to make it fly: thrust, drag, lift and gravity) (4 principle forces; act; on an airplane)
we 4 principle forces
know act
that there are 4 principle forces that act on an airplane to make it fly: thrust, drag, lift and gravity
on an airplane