How much energy is 500 joules?

500 joules is equal to 368.78 ft-lbf.

For example, an object has 500 joules of kinetic energy, when its mass is 10 kg (~22 lbs) and it is traveling at 10 m/s (36 km/h or ~38.2 ft/s).

Second example: The muzzle energy of a traveling 9mm bullet is around 500 joules.

Third example: An object with mass of 5kg (11 lbs) and which is raised at 10 metres (32.8 ft) has around 500 joules of potential energy.

So, 500 joules is quite much. Getting hit with an object which has 500 joules of kinetic energy can be lethal.