Work, Energy and power

Energy: Energy is the ability to do work. To do work on an object, energy must be transferred to an object. The SI Unit is joule (J) or kgm2/s2

Kinetic Energy: Kinetic energy refers to the energy due to a moving object. It is calculated by E_k = (1/2) mv² where E_k is kinetic energy, m is the mass of the object and v is the velocity of the object.

Potential Energy: Potential energy refers to the energy stored in an object.

–        Gravitation Potential Energy is stored in an object that is raised to a certain height above the ground. The formula to calculate is E_p = mgh where Ep is the gravitation potential energy, m is the mass of the object, g is the gravity field strength (10N/kg) and h is the height raised above the ground

–        Chemical Potential Energy is stored in food like vegetables and animals, and in fossil fuels and batteries.

–        Elastic Potential Energy is stored in a spring or a rubber band when it is compressed or stretched.

–        Thermal Energy is transferred from a region of higher temperature to a region of lower temperature.

Principle of the Conservation of Energy: It states that energy can neither be created nor destroyed. However, it can be transferred from one object to another or converted from one form to another. The total amount of energy is always the same.

Work: Work is done only when an object moves in the direction of the applied force. It is calculated by W = F x d where W is the work done, F is the force applied and d is the distance travelled by the object in the direction of the force

Power: Power, P, is the rate of work or the rate of energy conversion. The SI unit is watt (W). It is calculated by P = W/t = E/t where P is power, W is work done, E is the energy and t is the time taken. 1 W = 1 J/s