I did a simple experiment. I took a small block of copper (40g) and sensitive scales. First I cooled the block in a freezer (-2C) and checked its weight. Then heated it up to 300C in the oven and checked weight again. The difference in weight is well observed (4 - 5mg). Results are consistent and repeatable. The only conclusion I can make from it (apart from the obvious that many formulas in physics don't work in the real world) is that inertia and momentum also get affected with heat.