And, by Newton's 2nd Law, this must be equal to the mass times the y-component of the acceleration (since mass has no direction, and acceleration is also a vector). If we calculate (or just know) the x- and y-components of the net force acting on an object, it is a snap to find the total net force. An object of mass m is launched from a stationary helicopter towards the Earth with the speed v 0. It experiences a force of air resistance F = -kv, where k is a positive constant. It experiences a force of air resistance F = -kv, where k is a positive constant.
If F is the frictional force acting upwards between the passenger and the rotor wall and since there is no vertical motion of the passenger. F=mg. If μ is the coefficient of limiting friction between the passenger and the wall we have F=μN. Therefore, μN=mg, μ=mg/N=gr/v 2. Note that this is independent of the mass m.