How are work and energy related

The more work someone does, the more energy they need. For example, if someone is moving a large couch they are going to use a lot of energy because it is heavy. However, if the couch was smaller, they would be using less energy because it does not weigh as much as they will not become as tired!

Mg-26 and mg-24 are pair of isotopes. isotopes are defined as atoms of the same element having same atomic number but different mass number. i hope that was .