Assuming a constant L/D ratio, which of the diagrams provided correctly shows the movement of the "Thrust Required Curve". Mass m1 is higher than mass m2.
Refer to figure.
The Effect of Weight on Drag
If an aircraft is operated at a higher gross weight, more lift will be required. If more lift is generated, induced drag will be higher, total drag will be greater and VMD will occur at a higher IAS.
As the aircraft weight decreases (M1->M2), less lift is required which will reduce induced drag, moving the thrust required curve to the left. Due to the reduced weight total drag will be less and VMD will occur at a lower IAS, the thrust required curve moves downwards.
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