When a force acts upon an object to cause a movement or displacement of the object, it is said that work was done upon the object. There are three key ingredients to work - force, movement, and cause. In order for a force to qualify as having done work on an object, there must be a movement and the force must cause the movement. It is measured in joules.
The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object. The following equation is used to represent the kinetic energy (KE) of an object.
KE = 0.5 • m • v2 (where m = mass of object and v = speed of object)
A roller coaster ride is a thrilling experience which involves a wealth of physics. Part of the physics of a roller coaster is the physics of work and energy. The ride often begins as a chain and motor (or other mechanical device) exerts a force on the train of cars to lift the train to the top of a vary tall hill. Once the cars are lifted to the top of the hill, gravity takes over and the remainder of the ride is an experience in energy transformation.
At the top of the hill, the cars possess a large quantity of potential energy. Potential energy - the energy of vertical position - is dependent upon the mass of the object and the height of the object. The car's large quantity of potential energy is due to the fact that they are elevated to a large height above the ground. As the cars descend the first drop they lose much of this potential energy in accord with their loss of height. The cars subsequently gain kinetic energy. Kinetic energy - the energy of motion - is dependent upon the mass of the object and the speed of the object.
Sound energy is a form of energy that is associated with vibrations of matter. It is a type of mechanical wave which means it requires an object to travel through. This object includes air and water. Sound originates from the vibrations that result after an object applies a force to another object.
Electric energy is the energy created by electrons moving through an electrical conductor. The world is made of matter. All matter contains atoms that contain electrons that are always moving. When electrons are forced down a conductive path, such as a wire, the movement produces electricity, or electric energy.
examples of the principle of the conservation of energy
- In an electric bulb, electrical energy is converted into light and heat energy.
- In a microphone, sound energy is converted into electrical energy, while in a loudspeaker electrical energy is converted into sound energy.
- In a hydroelectric plant,, water falls from a height on to a turbine causing it to turn. The turbine turns a coil in a magnetic field, thereby generating a electric current. Therefore, potential energy of the water is converted into kinetic energy of the turbine, which is converted into electrical energy.