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A helicopter of mass 1000 kg rises with ...

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 the
(a) force on the floor by the crew and passengers
(b) action of the rotor of the helicopter on the surroundings air :
(c ) force on the helicopter due to the surroundings air :

Text Solution

Verified by Experts

Here, mass of the helicopter, `m_(1)=1000 kg`
Mass of the crew and passengers
`m_(2)=300 kg`
Upward acceleration `a = 15 ms^(-2)` and `g=10 ms^(-2)`
(a) Force on the floor of helicopter by the crew and passenger = appeared weight of crew and passengers
`= m_(2)(g+a)`
`=300 (10+15)=7500 N`
(b) Action of rotor of helicopter on surrounding air is obviously vertically downwards because helicopter rises on account reaction to this force.
Thus, force of action `F=(m_(1)+m_(2))(g+a)`
`= (1000+300)(10+15)`
`= 1300xx25=32500 N`
(c ) Force on the helicopter due to surounding air is the reaction. As action and reaction are equal and opposite, therefore, force of reaction `F^(1)=32500 N`, vertically upwards.
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