Why is energy measured in joules?

Answer 1

Work: You move a mass from A to B... the work doing this was defined by multiplying the force you used with the distance A to B.

Energy: i.e. the potential energy is defined by the gravity acceleration (g) multiplied with the mass (m) multiplied with the relative distance (h, usually from the ground) -> m*g*h. Now h is similar to a distance from a certain A to a certain B; force was defined by the multiplication of the mass and the acceleration the mass has... F (force) = m (mass)*a (acceleration), or in this case F = m*g.

Now it can be seen: energy of a mass on altitude h above the ground:

m*g*h = F*h = the work needed to lift the mass to this altitude... and as it is similar, the use of the same unit is logical.

Vic

because you move the mass

Answer 2

Heat is a form of energy, so it is measured in joule(j), the common unit of all kinds of energy .So, the scientist mainly measure energy in Joule

1 calorie = 4.2J

1 kacl = 4200J