A helicopter of mass M is rising vertically upwards with a uniform acceleration a. If the mass of the persons in the helicopter is m, what is the magnitude and direction of the force exerted by the persons on the floor of the helicopter?
m(g+a) vertically downwards
Let N be the normal force exerted by the helicopter on the persons in vertically upward direction.
Since the persons are rising upwards with the helicopter with an acceleration a, N−mg=ma⇒N=m(g+a)
Hence, the force exerted by the people on the floor will be F=m(g+a) vertically downwards and the correct choice is (a).