What happens to the kinetic energy of a system when it does work?

When a system does work, the energy associated with the system is transformed into different forms, correlating directly with the principles of energy conservation. When work is done, energy is not simply lost but is transferred or converted to other forms of energy, such as kinetic energy being transformed into potential energy or thermal energy, depending on the situation.

For example, when a car accelerates (doing work), its chemical energy from fuel is converted into kinetic energy, increasing the speed of the vehicle. Alternatively, when an object is lifted, the kinetic energy of the system is converted into gravitational potential energy. In both cases, energy is conserved, but it changes forms as the system performs work.

Other possibilities presented, like maintaining constant kinetic energy or losing energy to heat depend on specific conditions that don't apply universally. Therefore, the correct understanding is that kinetic energy, when work is done, is effectively transferred or converted to another form of energy.