I FK'ing Love Age Of Ultron

There are multiple inconsistencies with Ant-man's physics. Times when his mass is implied as consistent with his full-size mass:

- While ant-sized, Ant-Man falls from the edge of bathtub onto a tile floor, cracking the tile as though with the weight of a full sized human.
- He falls from a rooftop onto a car, denting the roof.
- He punches full sized humans, and they respond as though hit by a full-sized punch.
- He's able to judo-flip full sized humans
- Another character, while tiny, is hit by a speeding toy train. The train is knocked aside as though it hit a full sized human. 

And then there are times when their mass seems implied to be as light as their tiny size:


- Ant-Man is constantly running and climbing around on surfaces (air vents, ant tunnels, etc.) that couldn't possibly support the weight of a 200 lb man on a footprint the size of an ant.
- The toy train, when expanded to the size of a real train, is heavy enough to rip through a wall and crush a police car.
- Hank Pym carries a shrunken tank in his pocket on a keychain. It obviously doesn't weigh as much as a tank, but it does when expanded to full size.
- Another character, while tiny, gets swatted with a (normal sized) table tennis paddle, and goes flying like an insect.
- a flying ant is able to support Antman riding on it
- Antman riding on Hawkeye's arrow without affecting trajectory


And of course there's the fact that they specifically mention in the movie that his mass remains the same, and then is contradicted by the examples I stated above.