Types of Forces: Contact Forces, Non-Contact Forces, And Differences

Force is defined as the push or pull experienced by an object. It is a physical quantity that causes motion, opposes the motion, or changed the direction of motion of the body. 

• Force is a vector quantity and has both magnitude and direction.
• SI unit of force in Newton (N).
• It can be measured with a spring balance by hooking the object.
• Those forces which result when two interacting objects are perceived to be physically contacting each other is known as Contact force.
• Examples of contact forces are Muscular force, frictional force, tension, viscous drag, etc.
• Those forces which result without any physical contact are known as a Non-contact forces.
• Examples of non-contact forces are Magnetic force, Gravitational force, Electrostatic force, etc.

Key Terms: Force, Types of Forces, Contact Forces, Non-Contact Forces, Muscular Force, Frictional Force, Electrostatic Force, Gravitational Force, Magnetic Force, Differences

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What is Force?

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Consider two forces that are applied in the same direction. The resultant of these forces is in the direction of the greater force applied. Similarly, when two forces are applied in the opposite direction, the resultant force takes the direction of the greater force that is being applied. Newton is the SI unit of force (N).

The force formula is as follows:

F = ma

Where,

• F = Force Acting on the Body
• m = Mass of the Body
• a = Acceleration of the Body

Force Acting on an Object

Also Read: Unit of Force

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Types of Forces

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Based on the surface of contact between the object and the surface, there are two types of forces:

Contact Force

There are two types of forces in it:

• Muscular Force
• Frictional Force

Non-Contact Force

There are three types of forces:

• Electrostatic Force
• Gravitational Force
• Magnetic Force

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Contact Force

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Any force that needs a point of contact to exist is termed a contact force. This could also be when one object slides over another.

• Touch forces are generated only when two macroscopic groups of matter come into contact and are responsible for the most evident activities between them.
• Pushing an automobile up an inclined surface, kicking a football across a room or on a playground, moving any block from one location to another, and shifting big blocks from one location to another are all examples of contact forces in action.

Contact forces are classified as

1. Frictional Force
2. Muscular Force

Frictional Force

When one surface slides, rolls, or drags over another, the force that comes into action is termed frictional force. When we try to push an object, such as a book, across the floor, friction makes it harder.

• Frictional force, often known as opposed force, always acts in the opposite direction of the object's movement or attempt to move.
• A moving object's speed is always slowed by friction. 

The extent of frictional force exerted on an object is dependent on the materials employed in making the surfaces involved. More friction is produced as the roughness of the surface is increased. Friction generates heat as well. One may notice this when the hands are rubbed together quickly. The palms become warmer. Some examples of frictional forces in daily life are:

• The frictional force is beneficial because it keeps our shoes from slipping on the floor and automobile tires from skidding on the road as we walk.
• When you walk, the thread of your shoes rubs against the ground's surface, causing friction. This friction prevents slippage on the road by gripping the ground.
• Spikes are used in players' shoes to increase friction between the ground and the shoes, preventing them from slipping.
• To reduce friction during a cricket match, we utilize a granular substance in our hands.
• When we play carom, we normally sprinkle the powdered powder on the surface to reduce friction.

The frictional force is calculated as follows:

F = μN

Where,

• F = Force of Friction
• μ = Coefficient of Friction
• N = Normal Reaction Force

Frictional force Schematic diagram

Also Read:

Muscular Force

When we attempt to raise, bend, or otherwise disturb the other body's condition of rest, our muscles exert a force on it. Muscular force is the force that is exerted. Lifting an object, walking on the ground, jogging, bending, and boxing are just a few examples of activities that necessitate muscular force.

• It is a contact force since muscular force can only be exerted through physical contact, such as walking, running, jumping, and so on, or through contact with another person.
• Because our muscles are in direct contact with the object while applying force, muscular force is referred to as contact force.
• In simple words, it is a force that occurs as a result of muscle movement and is a contact force since two surfaces are in contact. Some everyday applications are:
• Strolling, lifting, getting up from a seat, and crossing a leg all involve muscular forces.
• In a tug-of-war game, the team that pulls the rope with the most force wins because the rope moves in the direction with the most force.
• When lifting a book or any other thing, we need to apply a force that is bigger than the object's reaction force.

Examples of Muscular Forces

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Non-Contact Force

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A non-contact force works on an object without really touching it. The most well-known non-contact force that determines weight is gravity. A contact force, on the other hand, is a force exerted on a body by another body that is in contact with it, or, in other words, forces that occur when two or more objects are not in contact.

Example of Non-Contact Force

Gravitational Force

Gravity, often known as gravitation, is the universal force of attraction that acts between all matter in mechanics. The weight of all bodies on Earth, or the downward force of the Earth is proportionate to their mass.

• The acceleration that gravity imparts to freely falling objects is used to quantify gravity.
• To put it another way, the gravitational force is the pull that the earth exerts on all objects on it.
• Everywhere we go, we are surrounded by gravitational force. It's with us when we're sitting, playing, walking, tossing, and just about anywhere else.

A gravitational attraction is exerted by any big celestial body, not just Earth. It can be higher, equal, or less than Earth's gravitational force, but it is always present. Because bodies with a bigger mass attract everything towards us, there is a gravitational pull on anything we are standing on if its mass is significantly greater than ours. 

Some daily applications are:

• The gravitational force causes a ball to descend to the ground when it is tossed up.
• The gravitational force causes water to always flow downward.
• The gravitational force causes an apple to fall when we throw it up.
• The fact that any fruit falls in a downward direction is due to the gravitational pull

It is denoted by the equation,

\(\color{red}{F_{g}=\frac{G m_{1} m_{2}}{r^{2}}}\)

Where

• F = Gravitational Force
• G = Universal Gravitational Constant
• m₁m₂ = Product of Masses of Two Bodies
• r² = Square of the Distance Between the Two Masses

Gravitational Force Exerted by Humans

Also Read: Fundamental Forces

Magnetic Force

Magnetic force is the attraction or repulsion that occurs between electrically charged particles as a result of their motion.

• The magnetic force is created by the mobility of charges and is a result of electromagnetism, one of the four fundamental forces of nature.
• In simple terms, a magnetic attraction force exists between two objects carrying charges moving in the same direction.
• When the charges of two items are opposing, they repel each other.

The following formula is used to compute it:

F = qvBsinθ

Where,

• F = Magnetic Force
• q = Charge of Moving Particle
• v = Velocity of the Particle
• B = Magnetic Field
• Sin θ = Angle Between Velocity and Magnetic Field Vector

Magnetic Force exerted by Magnets

Also Read: Sliding Friction

Electrostatic Force

The force between particles that are created by electric charges acting in an attractive and repulsive manner. The electrostatic force is the force that exists between stationary charged substances. Columba's Troops is another name for this group. The electrostatic force is the force that occurs between electrically charged particles or objects at rest, to put it simply.

Electrostatic forces can be seen in the following situations:

• When we use a comb to massage a small piece of paper with the oil in our head, we create electrostatic force.
• When one balloon is brushed with hair, the other is constantly drawn to it.
• Electrostatic charges cause silk garments to cling together after a while when ironed.
• The electrostatic force is also exemplified by lightning.

It is computed as follows:

\(\color{red}{F=k \frac{q_{1} q_{2}}{r^{2}}}\)

Where,

• F = Electrostatic Force of Attraction
• k = Constant of Proportionality
• q₁q₂ = Product of Charges of Two Bodies
• r² = Square of the Distance Between The Two Bodies

Also Read:

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Difference Between Contact and Non-Contact Forces

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Tabulated below are the differences between contact and non-contact forces.

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Things to Remember

1. The movement of any object (push or pull) that brings about a change in the object's characteristic properties is termed a force.
2. Force is broadly classified as contact and non-contact in nature.
3. When things on a surface try to move in relation to the surface, the frictional force is created. When a package is slid across a table, for instance.
4. Magnetic forces are the magnetic and electric interactions that help to bind and define the structure of solids. Poles attract each other, for example, in a magnet.
5. The gravitational force is the force operating between things as a result of the presence of matter. The gravitational force of the Earth, for example.
6. Frictional force, often known as opposed force, always acts in the opposite direction of the object's movement or attempt to move.
7. When we try to raise, bend, or otherwise disturb the other body's condition of rest, our muscles exert a force on it. Muscular force is the term for the force exerted.

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