He confirmed that Tesla intends to have the same cargo capacity as diesel trucks – meaning that it should weigh about the same as a diesel truck.

Hi Oren.

People forget, or neglect, that Elon is a trained physicist. He gave us 2 of the 3 variables to solve the F = M A equation during the reveal, and left the solution as an exercise for the class.

He gave acceleration from 0-60 mph at two different masses, 5 sec empty and 20 sec at 80,000 lbs gross weight. And we can assume F or motor force is the same under both tests.

From these two data points, it's trivial to show that the empty weight of the Semi is no more than 5s/20s = 0.25 of the max gross weight, or 20,000 lbs

And this places a limit on the max weight of the semi, since this calculation assumes zero extra rolling resistance from the trailer. So the semi weighs less than 20,000 lbs. And if we had data for the drag of the trailer, we could estimate the Semi's weight even more accurately

BTW, a standard Class 8 Semi weighs about 19,000 lbs.