If thrust exceeds drag, the airplane will accelerate.

If thrust exceeds drag, the airplane will accelerate.

• A. It will decelerate
• B. It will climb only if weight is reduced
• C. It will accelerate
• D. True

Answer: (D)

Net force along the flight path determines how the airplane speeds up or slows down. Thrust pushes forward, drag resists that forward motion, and Newton’s second law says a = F/m, where F is the net force. When thrust is greater than drag, the net force is forward, so the airplane accelerates. As speed increases, drag grows (drag is roughly proportional to velocity squared), so the acceleration will diminish and the aircraft will eventually reach a new higher speed where thrust once again balances drag. Weight and lift set vertical forces (affecting climb or level flight), but they don’t prevent forward acceleration when there is a positive net forward force. Therefore, the statement is true.

Net force along the flight path determines how the airplane speeds up or slows down. Thrust pushes forward, drag resists that forward motion, and Newton’s second law says a = F/m, where F is the net force. When thrust is greater than drag, the net force is forward, so the airplane accelerates. As speed increases, drag grows (drag is roughly proportional to velocity squared), so the acceleration will diminish and the aircraft will eventually reach a new higher speed where thrust once again balances drag. Weight and lift set vertical forces (affecting climb or level flight), but they don’t prevent forward acceleration when there is a positive net forward force. Therefore, the statement is true.