Mechanical simulation software

I hope I explain this right, but I’m looking for software that will allow me to build things. Maybe along the lines of mechanical simulations, I’m not talking about straight CAD or anything, I was something a little less complex. Something that’s physics related. I’ve played with bridge contruction software and I liked it. What I would like to do is have a clean slate of different parts and pieces that I can combine to make things and then test them. Here’s something I came across that kinda represents what I’d be interested in. It’s a battery and motor simulator. You select the type of battery and motors, change it’s properties, and then you can test it in a little vehicle while it displays battery life, amperage, volts, etc. I’d even settle for software that would allow me to build some of those robot wars type devices. Anything having to do with real world physics, machines, and building would be really kool to play with. Hope this makes sense.