In physics, a force is an influence which can change the motion of an object. Also, force is able to be described intuitively as a push or a pull. A force has magnitude and direction, making it a vector quantity. By the way, what is the unit for force in Physics? To find out the correct answer, you are able to read this entire article.
Definition of Force
Force can be defined as a push or pull which acts on an object. The force acting is able to stop a moving object, moving an object from rest, or changing the direction of its motion. It is based on Newton’s 1st law of motion, which states that an object continues to be in a state of rest or move with uniform velocity until an external force acts on it. Remember that force is a vector quantity because it has direction and magnitude.
The equation for force is given by Newton’s 2nd law. It is stated that the acceleration produced in a moving object is directly proportional to the force acting on it and inversely proportional to the mass of the object.
It can be written as: F= ma. Or in words, Force= mass x acceleration. Where the force in Newton is the mass of the object in. And, it is the acceleration of the body in. In other words, when the force acting on an object increases, its acceleration is going to increase provided the mass remains constant.
Unit of Force in Physics
The SI unit of Force in Physics is Newton. Usually, it is represented by the symbol F.1 N. It is able to be defined as a force which produces an acceleration of 1 m/s2 in an object of mass. Because forces are vectors, then their magnitudes can be added together based on their directions.
If the forces act in opposite directions, then the resultant force vector is going to be the difference between the two and in the direction of the force which has a greater magnitude. Two forces acting at a point in the same direction are able to be added together to produce a resultant force in the direction of the two forces.
As we said before, the unit for Force in Physics is Newton. In various applications, Newton is combined with other measurements.
Here are some applications of the newton:
- Moment of force
The unit of moment of force is the newton-meter (N-m), where m is the moment arm.
- Energy, work, and heat
The newton-meter (N-m) is the definition of the joule (J), which is a unit of energy. The units of kinetic energy E = ½mv2 are in kilogram-meter2/seconds2 and kg-m2/s2 = N-m.
- Power and radiant flux
Power is energy per second, with the unit of watt. Also, this is the unit for radiant flux or power from electromagnetic radiation.
The unit of pressure is the pascal (P) that is the force per unit area (N-m2).
Other Units of Force
Here are other units of force:
A dyne is the force required to give a mass of 1 gram an acceleration of 1 centimeter per second per second (1 cm/s2). 1 N = 100,000 dynes. You are able to use the dyne if you are working with small objects.
- Poundal and pound
A poundal is the force required to give a mass of 1 pound an acceleration of 1 foot per second per second (1 ft/s2). For your information, 1 poundal equals 0.1382 newtons. A pound is the force applied on a mass of 1 pound by the acceleration due to gravity. This is a non-technical unit of force. Also, it is called the weight.
Types of Force
We talk about how a force can be portrayed as a push or pull. A push or pull can happen when two or more objects interact with each other. However, forces can also be experienced by an object without any direct contact between objects occurring. Thus, forces can be classified into contact and non-contact forces.
- Contact Forces
The first type of force is contact forces. These are forces which act when two or more objects come in contact with each other. Well, let us look at some examples of contact forces below.
- Normal reaction force
The normal reaction force is the force that acts between two objects in contact with each other. The normal reaction force is responsible for the force you feel when you push on an object. And, its force that stops you from falling through the floor. The normal reaction force always acts normal to the surface. Thus, it is called the normal reaction force.
- Frictional Force
The frictional force is the force which acts between two surfaces that are sliding or attempting to slide against each other. Even a seemingly smooth surface is going to experience several frictions due to irregularities on the atomic level. Without friction opposing the motion, objects will continue to move with the same speed and in the same direction as stated by Newton’s 1st law of motion.
- Non-contact Forces
The second type of force is non-contact forces. These forces act between objects even when they are not physically in contact with each other. Well, let us look at some examples of non-contact forces below.
- Gravitational force
Gravity is the attractive force experienced by all objects which have a mass in a gravitational field. Gravitational force is always attractive, and on the Earth acts towards its center. Need to know that the average gravitational field strength of the earth is 9.8 N/Kg. The weight of an object is the force from its experiences due to the gravity. It is given by the following formula: F= mg
- Magnetic force
A magnetic force is the force of attraction between the unlike and like poles of a magnet. The south and north poles of a magnet have an attractive force while two similar poles have repulsive forces.