Algodoo

Guys thank you for responce but take a look at my "brand new quite old trollerbus" I spent so much more time and love for it

In the middle of track I thought "no way I can drop that boxes" and seconds later I lost one, then it got stuck under the wheels

Definitely underrated. You should add in-game instructions

Interesting but too stiff. Multiplying mass by 4 gives much more realistic results.
Aaaand... Its weight is 5 kgs. Made of styrofoam.

5th seems like on of the easiest