Work and Energy  

Work and energy are the most used terms in Physics. Both work and energy are the two sides of the same coin. Let us understand their meaning in-depth in this article.

Work

The logical meaning of work is distinctive from multiple points of view from its ordinary importance. The meaning of work in material science uncovers its relationship to energy. At whatever point work is done, energy is transformed. In physics, work is the energy moved to or from an object through force along a displacement. In its easiest structure, it is frequently spoken to as the result of force and displacement. A force is said to accomplish positive work if (when applied) it has a segment toward the displacement of the purpose of utilization. A force accomplishes negative work in the event that it has a part inverse to the course of the displacement at the purpose of use of the force.

For example, when a football is held above the ground and then suddenly dropped. The work done by the gravitational force on the football as it falls is equal to the weight of the ball. That is a force multiplied by the distance to the ground as if a displacement.

Work = Force × Displacement

When the force is and the angle between the force and the displacement s is \(\theta\). Then the work done is:

W = \(F cos\theta.s = F.s\)

Where,

• W is the work done by the force
• F is the force
• s is the displacement caused by the force
• \(\theta\)is the angle between the force vector and the displacement vector

The dimension of work is the same as that of energy. It is given as, [ML²T^-2].

Work is a scalar quantity. Thus, work has only magnitude and no direction. Work done transfers energy from one place to another, or transfers from one form to another. The SI unit of work is the joule (J). It is a unit similar for energy.

Energy

In physics, energy is the quantitative property. Thus, energy must be transferred to an object in order to perform work. Energy is a conserved quantity. The law of conservation of energy states that the energy can be converted in form. It can neither be created nor be destroyed. The SI unit of energy is the joule. This energy transferred to an object. This is done by the work of moving it a distance of 1 metre against a force of 1 newton.

Mass and energy are closely related to each other. According to mass-energy equivalence, if any object that has mass is stationary or rest mass also has an equivalent amount of energy whose form is called rest energy. Any additional energy (of any form) acquired by the object above that rest energy will easily increase the object’s total mass similarly it increases its total energy.

Types of Energy

Some common forms of energy include the kinetic energy, it is of a moving object. The potential energy is stored by an object’s position in a force field. It can be gravitational, electric or magnetic. The elastic energy is stored by stretching solid objects. The chemical energy that is released when a fuel burns. The radiant energy that is carried by light. And the thermal energy, it is due to an object’s temperature.

Some other types of energy are below:

• Mechanical energy
• Mechanical wave energy
• Chemical energy
• Electric energy
• Magnetic energy
• Radiant energy
• Nuclear energy
• Ionization energy
• Elastic energy
• Gravitational energy
• Thermal energy
• Heat Energy

FAQs on Work and Energy

Q.1. When a body falls freely under gravity, the work done by gravity is positive or negative?

If a force is acting on a body that has a component in the direction of displacement, then the work done by the force is positive. Therefore, when a body or an object falls freely under the influence of gravity the work done by the gravity is also positive.

Q.2. Can energy be stored?

Yes, energy can be stored. One best way to store energy is in the form of chemical energy i.e., in a battery. When we connect a battery in a circuit, energy in the battery releases and it produces electricity. We can easily store energy in many other ways too. For instance, Batteries, gasoline, natural gas, food, water towers, a wound-up alarm clock, a Thermos flask with hot water all of the stores of energy.