Energy is defined as the ability to do work, distinguishing it from matter, forces, or chemical substances. This basic concept is fundamental in understanding various energy forms.

Kinetic energy is the energy of motion, and a moving car clearly exhibits this. The other options involve objects that are at rest.

Food contains chemical energy that is stored in its molecular bonds. This energy is released during metabolic processes when food is digested.

Kinetic energy is the energy an object possesses because of its motion. Other forms like potential or nuclear energy relate to stored energy or atomic changes.

Thermal energy is directly related to the temperature of a substance and is used to heat spaces. The other energy forms do not primarily produce heat.

Gravitational potential energy is stored in an object due to its elevation relative to the ground. The higher the object, the greater the energy stored.

The law of conservation of energy states that total energy remains constant in a closed system despite energy transformations. Energy cannot be created or destroyed, only converted from one form to another.

Rubbing hands creates friction which converts mechanical energy into thermal energy, warming the hands. This everyday phenomenon illustrates energy transformation through friction.

Electrical energy is often generated by converting mechanical energy to electrical energy using turbines. These turbines are typically driven by steam, wind, or water motion.

Renewable energy comes from natural sources like the sun, wind, and water that are replenished naturally. This differentiates it from fossil fuels which are finite and non-renewable.

Coal is a fossil fuel that is extracted from the earth and is not replenished naturally in a short time span. The other options are renewable energy sources that can be naturally restored.

Nuclear energy is released during the process of splitting atomic nuclei (fission) or joining them (fusion). This is fundamentally different from energy stored in chemical bonds or produced by mechanical means.

A battery stores energy chemically within its cells. When connected to a device, this chemical energy is converted into electrical energy to power electronics.

In a light bulb, electrical energy is converted into light energy, and some energy is also released as heat. This conversion demonstrates the transformation between different energy forms.

The conservation of energy principle explains that energy cannot be produced or destroyed, only transformed. This understanding is vital for analyzing how energy moves and changes form in different systems.

During collisions, mechanical energy is often converted into other forms like thermal and sound energy due to friction and impact. This transformation ensures that the total energy remains conserved within the system.

On a roller coaster, energy shifts between potential and kinetic forms as the ride moves along its path. Despite these conversions, the total energy remains nearly constant, clearly illustrating the conservation of energy principle.

Elastic potential energy arises from the deformation of an object, such as stretching or compressing a spring. In contrast, gravitational potential energy depends on an object's height relative to Earth.

Energy efficiency is measured by how well input energy is converted into productive work. Focusing on the conversion ratio reveals losses that occur during energy transformations.

In real-world systems, inefficiencies like friction convert a portion of useful energy into heat, making it seem as if energy is lost. However, energy is conserved; it is merely transformed into a less useful form.