No one has yet described force better than Aristotle. He famously described a force as anything which causes an object to undergo ‘unnatural motion’. In terms of physics, a force is any form of influence that leads a free body to accelerate. A push or a pull, which can cause an object to change its velocity, is a type of force. Since a force has both magnitude and direction, it is a vector quantity. There are different types of forces that operate on a body, each different in origin and characterization. However, there are four fundamental forces in nature which govern every interaction. The rest of the forces are simple manifestations of them. The four fundamental forces are gravitational force, electromagnetic force, weak nuclear force and strong nuclear force. In the following lines, we have provided an exhaustive detail of the different types of forces.
Different Kinds Of Forces
Gravitation is the agent which gives weight to objects with mass and causes them to fall on the ground when dropped. Generally speaking, gravitation causes the dispersed matter in the universe to come together. It is the gravitational force that helps the earth and other planets to stay in their respective orbits around the sun. Gravitational force is also responsible for keeping the moon revolving around the earth, for tidal formations, for natural form of convection and innumerable other minor and major phenomena observed in our day-to-day living. While Isaac Newton defined gravity as a force that attracts all objects to each other, Albert Einstein used the general theory of relativity to explain the concept of gravity. He described that gravitational force was the consequence of the curvature of space-time, which, in turn, governs the motion of inertial objects.
An electromagnetic force is a particular force or influence that affects charged particles. The photons are messenger particles of an electromagnetic force and are responsible for holding the electrons and protons together in an atom as well as holding the atoms together in a molecule. These particles may be positively or negatively charged. The photons have no individual mass and possess the ability to travel at the speed of light. So, they are easily able to carry the force and attract the electrons and protons together. Electromagnetic force forms the core of the theory of electromagnetism, which explains the relationship between electricity and magnetism. The electromagnetic force plays a role in friction and is a central tenet in Einstein’s Theory of Relativity. Although this force is present practically everywhere, its presence can be proved by the presence of electrically charged bodies, which are either positive or negative. Neutron particles which are neutrally charged are completely immune to it. The electromagnetic force follows the inverse square law, which signifies that the strength of the force is inversely proportional to the square of the distance from the source of the force.
Weak Nuclear Force
The weak nuclear force is one of the four fundamental forces of nature and is also known as weak interaction. This force underlies few forms of radioactivity, governs the decay of unstable subatomic particles such as mesons, and initiates the nuclear fusion reaction that fuels the sun. The weak nuclear force acts upon fermions, which are elementary particles with half-integer values of intrinsic angular momentum or spin. These particles interact with the help of weak nuclear force by exchanging the force-carrier particles known as W and Z particles. The particles are heavy, with a mass content of 100 times the mass of a proton. It is this heaviness, which defines the extremely short range nature of this particular force.
Strong Nuclear Force
It is one of the four basic forces in nature and as the name implies, it is the strongest of all. Since it has the shortest range, the particles should be extremely close to each other for the effect to be felt. What it actually does is holds the subatomic particles of the nucleus together. We all know that opposites attract. So, two positively charged protons present in an atom should repel each other. This is where the working principle of nuclear force comes in. The strong nuclear force is created between nucleons (protons and neutrons) with the help of exchange of particles called mesons. The nucleons should be closely placed for this exchange to take place.
- Applied force is a type of force which is applied to any object by a person or any other object. For instance, if you pull a chair in order to sit on it, there is applied force acting upon the chair. The force applied by you on the chair is nothing but applied force.
- Frictional force is the force exerted by a surface on the object moving across it or trying to move across it. The two basic types of frictional force are sliding and static friction. Air resistance force is a special category of frictional force, which acts upon objects traveling through air. It actually opposes the motion of the object in air.
- The tension force is a force transmitted through a string, rope, cable or wire, while it is pulled by opposite forces acting on the other end.
- The spring force is a force which is exerted by a compressed or stretched spring upon a specific object attached to its end. Usually, the magnitude of the force is directly proportional to the amount of stretch or compression of spring.