Effects of Force: Definition, Types and Sample Questions

Force is referred to as an influence such as a push that leads to a change in the velocity of an object or causes it to store energy through deformation. When a force is applied to an object, the object undergoes some changes. In this article, we will discuss the definition of force, different types of force, and the effects of force. 

Keyterms: Force, velocity, effects of force, types of force, Newton, acceleration, magnitude, resistance

Read More: Balanced and Unbalanced Forces

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What is Force?

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Force is an influence, a type of push or a pull, that leads to an object (with a certain mass) changing its velocity. In other words, it introduces acceleration in an object. Force is a vector quantity i.e. it has both magnitude and direction. The SI unit of force is Newton (N) and it is represented by the symbol ‘F’. 

Types of Force

Different types of forces that are found in nature can be broadly categorized into two types: 

1. Contact Force
2. Action-at-a-distance Force

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Contact Force

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As the name suggests, the Contact Force comes into play when two objects are in contact with each other. There are various examples of the Contact Force in nature such as pulling a cart, a ball rolling on the ground stops due to friction, a streamlined body of an airplane to minimize air resistance, etc. 

Contact Forces can further be divided into the following types: 

• Applied Force: It is the force that one object exerts on the other object directly. For example, pushing a door, hitting a ball with a hockey stick, opening a drawer, etc. 
• Frictional Force: Frictional Force is a type of Contact Force that opposes the movement of an object on a surface. In other words, it is a resisting force. For example, a ball rolling on a floor slows down and eventually stops, applying brakes to stop a vehicle, writing on a notebook, etc. Frictional Force is of two types: Static Friction and Dynamic Friction. 
• Air Resistance Force: Just like a surface opposes the movement of an object, the air opposes the objects moving through it. This type of force is called the Air Resistance Force. The strength of the Air Resistance Force depends on the speed and the surface area of the object. Examples of Air Resistance Force are a person who is skydiving slows down because of the parachute, riding a bicycle, walking in a storm, etc. 
• Tension Force: Tension is a type of pulling force that is transmitted through a string, cable, etc. It acts along the string and exerts equal pressure at both ends. For example, drawing a bucket of water from a well, playing tug of war, weighing using a spring balance, etc. 
• Spring Force: Spring Force is exerted by a spring and it comes into play when a spring is stretched or compressed. Some examples that involve Spring Force are trampoline, shock absorbers in vehicles, spring balance, etc.

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Action-at-a-Distance Force

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Action-at-a-Distance Force is exerted without the objects being in contact. The various types of Action-at-a-Distance Force are as follows:

• Gravitational Force: Gravitational Force is a universal force. It is a type of attractive force that explains the tendency of objects to fall towards the Earth. Gravitational Force is responsible for attracting any two objects with mass. Examples of the Gravitational Force are objects falling back on the Earth when thrown in the air, the working of our solar system is the result of the Sun’s gravitational force on other planets, etc.
• Magnetic Force: Magnetic Force is the force of attraction or the force of repulsion that is exerted by the electrically charged particles due to their motion. Examples of Magnetic Force are motors, compasses, train tracks, etc. 
• Strong Nuclear Force: Strong Nuclear Force is responsible for the integrity of the atomic nucleus. It is exerted over very short distances.
• Weak Nuclear Force: Weak Nuclear Force comes into play during atomic decay. Its range is even shorter than that of the Strong Nuclear Force. 
• Electrical Force: Electrical Force is the force of attraction or repulsion exerted between electrically charged particles. It is different from Magnetic Force as the charges are at rest in this case. Examples of Electrical Force are the charge in a bulb, electrical circuits, the attraction between two balloons when one of them is rubbed with hair, etc. 

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Resultant Force

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Resultant Force is the sum total of all the forces that act on an object. It is mainly responsible for the velocity change of an object. 

• If the resultant of all the forces is zero, it means that all the forces are balanced. 
• In this situation when the resultant force is zero, the object will stay at rest. 
• When the forces are unbalanced i.e. the resultant of all the forces is non-zero, the object starts moving in the direction of the net resultant force. 

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Effects of Force

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Certain effects can be observed when a force is applied to an object. These effects are listed below. 

• Setting any stationary object in motion: An object tends to start moving when a force is exerted on it. The movement is in the direction of the force applied. For example, when you hit a ball with a hockey stick, the ball starts moving in the direction in which the force was applied through the hockey.
• Stopping or slowing down a moving object: A moving object can be slowed down or stopped by the application of force. For example, applying brakes to stop the car. Here, the car stops due to frictional force. 
• Changing the direction of a moving object: The direction of an object moving in a particular direction can be changed by exerting force. For example, a batsman hits the ball with the bat (exerting force) to change the direction of the ball. 
• Changing the speed of a moving object: An object moving at a constant speed can be accelerated with the application of force. For example, a ball moving at a constant speed will roll faster after being hit. 
• Changing the shape of an object: Force can also deform an object. For example, we can make different shapes with clay by exerting force on the mold. 

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Things to Remember based on Effects of Force

• Force is an influence that can cause an object (with mass) to change its velocity.
• Force is of two types: Contact Force and Action-at-a-Distance Force.
• Contact Force comes into play when two objects are in contact with each other.
• Action-at-a-Distance Force is exerted without the objects being in contact.
• Force tends to change the speed, shape, and direction of an object. 
• Force can set a stationary object to move or slow down/stop an object in motion. 
• Resultant Force is the sum total of all the forces that act on an object.