Relationship Between Energy, Work, and Heat
We’re going to take a look at the relationship between energy, work, and heat. First, we have kinetic energy, which is just energy by virtue of motion. Kinetic energy is related to both mass and velocity.
The equation for kinetic energy which I’m just going to abbreviate kinetic energy is capital KE. The equation for that is 1/2 times mass times velocity squared. Then we have potential energy which is stored energy.
This energy can be by virtue of the objects position which we call gravitational potential energy. I’m just abbreviating potential energy as PE. If the object has a certain position where it could fall that would give it gravitational potential energy.
There’s also chemical potential energy which is stored and chemical bonds. The energy is stored up in the chemical bonds of molecules and those bonds can break that’s why it is potential energy. Then we have thermal energy which is internal energy.
We measure this internal energy by temperature. Objects have internal energy by virtue of the motions of the atoms and molecules that make them, that’s why they have this internal energy.
Now, if we were going to define energy, we could define it as: the ability to do work or transfer heat. The energy unit that we use for energy is joule which is usually just going to be spelled with a lowercase j but, we’re going to abbreviate it with a capital J like that.
Again, energy is the ability to do work or transfer heat and energy can be transferred to and from objects by doing work, applying a force through a distance, or a pressure on a volume. Energy can also be transferred as heat. For example, when ice is placed in liquid water, the water transfers energy in the form of heat to the ice and the ice melts. That’s why energy is the ability to do work or transfer heat.