So how does THIS work?

[ptc-2641386]

I'm a bit new to this program, but I think it can help me get to some solutions I need for a proposal I'm working on and I'm having trouble with units, or variables, or something. This equation relates to traffic throughput based on variables such as speed and car spacing, solving for Q, which is obviously the quantity of traffic over a period of time. Ultimately I want to be able to show a series of graphs showing the effect of changing some of these variables. But I can't figure out how to get mathcad to deal with a unit that has no equivalent (like cars), just is what it is. If I do this manually, I solve for cars/hour, but I can't get mathcad to look at it this way.

[RichardJ]

User defined dimensions have been requested multiple times. Until we get them, you have two options. One is to just set car:1. It gets rid of the red, but of course Mathcad will not track the car unit. The other option is to hijack the Money dimension, since you are probably not using it for anything else. Set car equal to 1 unit of base currency. When you evaluate an expression you will see the base currency unit in the result, so you will have to override that by typing your units into the units placeholder. Richard

[ptc-2641814]

I'd be inclined to leave N as a pure, dimensionless number. (ie. N = 20) Keep everything else with its units. And then you will get Q with dimension 1/hour - things per hour.