A jet plane is traveling at a constant speed in a straight line in level speed. What does this tell you about the forces acting on it, what forces are acting on it .

Answer 1

The net force must be zero at constant speed, since there is zero acceleration.

In the vertical direction, the weight force is balanced by the lift force on the wings (mainly)

In the horizontal direction, wing and fuselage drag is balanced by jet engine thrust.

Answer 2

Thank you so much, i understand a lot more now !

Answer 3

Good! Physics is fun once you get the hang of it.