Listed following are three possible models for the long-term expansion (and possible contraction) of the universe in the absence
of dark energy. Rank each model from left to right based on the ratio of its actual mass density to the critical density, from smallest ratio (mass density much smaller than critical density) to largest ratio (mass density much greater than critical density). (A) coasting universe
(B) critical universe
(C) recollapsing universe
The friction force is the weight force times the coefficient of friction. So diving by the coefficient gives you the weight force which is equivalent to the normal force.
