# How do gas laws apply to make a cannon work?

Jul 2, 2015

When gunpowder (or another explosive) burns a lot of gas is formed.

#### Explanation:

This alone would create pressure. But the gas is also heated. This would create even more pressure. All according to the formula:

$p = \frac{n \cdot R \cdot T}{V}$

Where $p$=pressure, $n$=amount of gas, $R$=a constant, $T$=temperature and $V$=volume.

When $n$ and $T$ are rising rapidly during the explosion, the pressure builds up. Since the walls of the canon are able to withstand this pressure (we hope!), the effective force is directed to the projectile, which will be accellerated into the barrel. Once it leaves the barrel, it will have reached a certain speed, called the muzzle velocity, and it will be accellerated no more. This is one reason why long-range guns have long barrels.