Marlin Firearms Co. Est. 1870

passenger elevator system

Consider a man of 70 kg mass is traveling on an elevator. The motion of the lift is directed vertically and is uniformly accelerated with acceleration a (write all scalar quantities in the game as being directed along the z axis of an orthonormal reference system).
In the scheme of the problem is indicated by the weight of the passenger W (W = 70 kg * 9.80 m / s ^ 2 = 686 N) with R and the force exerted on it from the floor. Note that the third law of motion for R is always equal in magnitude and opposite in direction to the force exerted by the passenger on the floor. The quantities involved are considered positive if it agrees to the z axis drawn in the figure, negative otherwise. Applying the second law of dynamics is written
F = ma, or

R - W = ma, where a is the acceleration
system + passenger lift.
So if for example a = 0.5 m / s ^ 2 (positive, ie upward), we get
R = 70 kg * 9.80 m / s ^ 2 + 70 kg * 0.5 m / s ^ 2 = 721 N,
The passenger, still in the frame of the lift, the feeling of more weight than usual. The 'apparent weight' of the passenger (in the form of the force he exerts on the floor and vice versa) is in fact higher than it would if the elevator was at rest or of uniform motion moved, was that a reference system INS. This could occur by placing the passenger on a dynamometer attached to the floor of the elevator. Where a = -0.5 m / s ^ 2, is
R = 70 kg * 9.80 m / s ^ 2 - 70 kg * 0.5 m / s ^ 2 = 651 N,
The passenger exerts less force on the floor if the direction of acceleration is opposite to the axis z. The example on display is very easy for example reflected in daily life: we can easily realize on the floor to exercise a power greater than our normal weight every time we are in an accelerated upward (lift or games of amusement parks) , the lower when the environment in question is accelerated towards the low.
An interesting case is that of free fall if the lift cable was cut, the system + passenger elevator would fall freely toward the Earth with acceleration a =-g. Then R would be nothing, the passenger and the floor is not exerting any force on each other and the apparent weight of the passenger (possibly indicated by the dynamometer) would be zero.