Potential energy, types, and examples.
Potential energy is referred to as the energy possessed by a physical body with reference to other bodies, etc. It is the energy of a system, not the individual body or an object.
Potential energy is referred to as the energy possessed by a physical body with reference to other bodies, or objects, internal stress, elastic charge, or condition of the body. It is the energy of a system, not the individual body or an object. That system may include more than one object and forces applied to it.
Let us take an example of a raised hammer, where the system includes a hammer, gravitational force acting against the raised hammer, and the individual who raised it. Now the raised hammer possesses the potential energy due to its height above the surface level and mass.
The potential energy of the above system of the hammer depends on its initial and final position and it has nothing to do with the path of its travel. Hence it is independent of the path it travels. Now we may calculate the gravitational potential energy of the system as such;
where m is the mass of the object, g is the acceleration due to gravity,(On the earth the value of g is 9.8m/s2.) h is the height of the object from the referred ground level and Ug is the gravitational potential energy in joules.
The term “potential energy” was first introduced in 1853 by Scottish engineer and physicist William Rankine.
Types of Potential energy;
Potential energy is the stored energy of the system as it has the potential to perform a certain task when released. It can be divided into the following types, such as gravitational, elastic, nuclear, chemical, electric potential energy, etc. Further, it may be transformed into other forms of energy like kinetic energy.
Gravitational Potential energy;
In the Gravitational Potential energy system, the gravity of the earth and the object at a relatively high position of the earth are taken as the parts. If out of two bricks of the same mass one is kept on the 10 feet high roof and another brick is kept on an 8 feet-high roof in such a case, the brick at 10 feet height has more potential energy than the brick at 8 feet height.
In such cases, the height of the object along with its mass is an important factor for the calculation of gravitational potential energy. Once the brick hits the ground, it will have no potential energy. The ground is the zero potential for gravitational potential energy. This value of potential energy is arbitrary and relative to the choice of a preferred point on the ground because if the earth of the ground is removed the brick would continue to fall.
More examples are;
- A raised hammer.
- A book on the shelf before it falls.
- Coconut in the tree before it falls.
- A child at the top of the slide ready to slide.
- Flood water behind the gates of a dam.
- The water behind the waterfall.
Elastic potential energy;
The energy is stored in the elastic objects by virtue of external forces for compressing or stretching from both sides. Unless the external forces are removed the elastic energy remains stored. An object like a spring or a rubber band can have elastic energy. In the other words, any elastic body has potential energy stored in a system when it is deformed. The formula of such energy can be written as;
where U is elastic potential energy, k is spring force constant, and ∆x is the string stretch length in meters. The examples are as follows;
- A stretched rubber band.
- An elastic ball.
- An archer’s bow with pulled back string.
- A stressed or stretched spring.
- A football ready to be kicked.
Nuclear potential energy;
Nuclear energy is often referred to as nuclear potential energy. Nuclear energy is stored in the nuclei of atoms. When atoms are merged or fusion is made or the atoms are split or fission is done the stored energy is released in nuclear reactors.
Chemical potential energy;
Chemical potential energy is the energy stored in the chemical bonds of the chemical substances. It is released when it reacts with another chemical substance. Some examples are as such;
- Charged batteries.
- Fruit juice before it is fragmented.
- Gasoline is ready to ignite.
- Iron before it is getting rusts.
To know more may go through the post, chemical energy with important examples.
Electric potential energy;
Electric potential energy is the stored energy of a charged capacitor. In other words, we may say that the energy needed to move a charge against the electric field is electric potential energy. In such cases, if two, unlike charges,( a negative and a positive) are brought toward each other the electric potential energy of the system will decrease. Whereas if two like charges ( two negative or two positives) are made close to each other the potential energy will increase in a system. All electronic devices when in the off mode possess the potential energy. Some examples;
- A cellphone that has been turned off.
- Car headlights before they are turned on.
- Solar cells at night.
- A television before it’s switched on.
- A computer before it is turned on.
- Smartwatches when turned off.
- Electric generator after turning on.
- A washing machine when turned off.
Magnetic potential energy;
Magnetic potential energy is often referred to as the position of a magnetic object within a magnetic field. Like gravitational potential energy, the position of an object in the electric field affects the magnetic potential energy. It is the energy stored due to attractive forces between two objects.
Any metal reacts more strongly to a magnetic field than a nonmetal. A non-metal like plastic or rubber may have zero effect by a magnetic field. The magnetic potential energy of a magnetic dipole has a uniform magnetic field. Some examples of magnetic potential energy are as follows;
- ball bearings.
- metal spoons.
- electric motors.
Potential energy is essential for understanding energy. The total work done by the force on the object depends on the initial and final position of the object irrespective of its path of movement. Such energy has the potential to convert into the energy of motion known as kinetic energy. Potential energy includes gravitational potential energy, elastic potential energy, chemical potential energy, electric potential energy, nuclear potential energy, magnetic potential energy, etc.