Question

A helicopter of mass 2000kg rises with a vertical acceleration of 15 m s^–2. The total mass of the crew and passengers is 500 kg. Give the magnitude and direction of the (g = 10 m s^–2)

a) force on the floor of the helicopter by the crew and passengers.

(b) action of the rotor of the helicopter on the surrounding air.

(c) force on the helicopter due to the surrounding air.

Answer 1

(a) F - (500 ×10) = (500 × 15) or F = 12.5 × 10³ N, where F is the upward reaction of the floor and is equal to the force downwards on the floor, by Newton’s 3rd law of motion

(b) R - (2500 × 10) = (2500 × 15) or R = 6.25 × 104 N, action of the air on the system, upwards. The action of the rotor on the surrounding air is 6.25 × 10⁴ N downwards.

(c) Force on the helicopter due to the air = 6.25 × 10⁴ N upwards