The four forces acting on an A/C will be in equilibrium when the aircraft is in _______ level flight.
A.accelerating
B.decelerating
C.unaccelerated
D.accelerated
正确答案是C
The four forces acting on an A/C will be in equilibrium when the aircraft is in _______ level flight.
A.accelerating
B.decelerating
C.unaccelerated
D.accelerated
正确答案是C