A helicopter flies through the air. The thrust is 100,000 N and the drag is 80,000 N. The lift force is 90,000 N and the weight is 90,000 N. What is the net force?
1 Answer
Explanation:
We're asked to find the net force acting on the helicopter, given the four forces acting on it in air.
Thrust, drag, lift, and weight are sometimes called the four forces of flight:
(I am aware the question regards a helicopter.)
We can find the components of the net force by finding the net horizontal force and the net vertical force acting on the helicopter.
Horizontal:
The two horizontal forces are thrust and drag (from image), so the net force can be found by subtracting the drag force from the thrust force:
#100000# #"N"# #- 80000# #"N"# #= color(red)(20000# #color(red)("N"#
Vertical:
The two vertical forces are lift and weight, and the net force is thus
#90000# #"N"# #- 90000# #"N"# #= 0# #"N"# Which means the helicopter is moving only in a horizontal line, and its height is not changing.
Net Force:
The magnitude of the net force is usually found by using the distance formula and the net force components, but there is no net vertical force, so the net force is just the horizontal component:
directed forward (thrust propels the helicopter forward; if the drag is larger in magnitude, the helicopter goes backward!)
