A freight elevator of mass M M\,M is accelerating upwards at a rate of aaa. It is pulled upwards by a cable tension T T\,T against a constant gravitational acceleration g g\,g and a constant frictional drag force FFF.
Using Newton's second law, the equation of motion is:
T−Mg−F=Ma T - Mg - F = Ma T−Mg−F=MaWhich of the following is the correct expression for the mass MMM?
M=T−Fg−aM = \frac{T - F}{g - a}M=g−aT−F
M=T+Fg+aM = \frac{T + F}{g + a}M=g+aT+F
M=T−Fg+aM = \frac{T - F}{g + a}M=g+aT−F
M=g+aT−FM = \frac{g + a}{T - F}M=T−Fg+a