We will have the following:
The first law of Thermodynamics:
Energy cannot be created or destroyed, it can only be transformed.
An example is when a car suddenly breaks in order to avoid hitting a person, here the velocity of the car, all the energy that is acumulated is transformed into thermal energy and it disipated by the friction of the breaks and the tires. The total energy of the system will remain the same, but it will change the way the energy is present. This as per our understanding of the universe so far.