A helicopter of mass 1000 kg rises with a vertical acceleration of 15 ms^{-2}. The crew and the passengers weigh 300 kg. Give the magnitude and direction of

**(a)** force on the floor by the crew and passengers,

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

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

Asked by Abhisek | 1 year ago | 83

Mass of helicopter = 1000 kg

Crew and passengers weight = 300 kg

Vertical acceleration, a = 15 ms^{-2} and g = 10 ms^{-2}

The total mass of the system, m_{i }= 1000 + 300 = 1300 Kg

**(a)** Force on the floor of the helicopter by the crew and passengers

R – mg = ma

= m (g+a)

= m (g + a) = 300 (10 + 15) N = 7500 N

**(b)** Action of the rotor of the helicopter on surrounding air is due to the mass of the helicopter and the passengers.

R’ – m_{i}g = m_{i}a

R’ = m_{i} (g+a)

= 1300 x (10 + 15) = 32500 N

This force acts vertically downwards

**(c)** Force on the helicopter due to the surrounding air is the reaction of the force applied by the rotor on the air. As action and reaction are equal and opposite, therefore, the force of reaction, F = 32500 N. This force acts vertically upwards.

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