What is Force?
In general terms, we say that the push or pull of an object is force, but what does this mean?
A force is defined as the application of push or pull on an object with a mass in such a way that it will affect the motion of an object when unopposed. It can cause an object to move from its state of rest, i.e., change its velocity (to accelerate) or can change its direction of movement. It is an interaction that causes or changes the motion of an object. When a force is applied, it has both magnitude and direction. Hence, it is a vector quantity.
It is denoted by the symbol F and its S.I. unit is Newton (N). The other units of force are dyne,kgwt, etc.
Now, let us understand the push and pull force in basic language.
What is a Push Force?
Push is defined as a force that causes an object to move away from the person who is applying the force from its state of rest. When an object is pushed, it tends to move away. Kicking a ball, closing a door, pushing a trolley, and inserting a plug into the socket are all examples of push force.
Assume that you are asked to push a lawn roller or push the luggage from the stairs and throw it on the floor. For this, you will have to put an effort and that effort you apply through your feet to the object you are pushing is the push force. Applying this force is easier; however, there is another category of force that demands a lot of energy from your end. This force type is called the pull force. Now, let us understand what it is!
What is a Pull Force?
The pull is defined as a force that causes an object to move towards the person who is pulling the object. Opening a door, plucking the string of a guitar, drawing a bucket of water from the well, and pulling the curtain are all examples of pull force.
So, this was all about the force in general. Now, let us understand its types.
Types of Forces
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A force can be applied to an object in two ways, i.e., by making a contact with the object or by not making a contact with the object. Based on that, there are two types of forces. They are known as contact forces and non-contact forces.
Contact Force
A contact force is defined as a force that requires a contact to apply a force on an object. Kicking a ball and closing a door are all examples of contact forces because contact is made in each case. It is further classified into three forces, namely, frictional force, applied force, and normal force.
Frictional Force: When a ball is softly kicked, it rolls over the floor. At that time, a force acts opposite to the direction of the moving ball which eventually stops the ball. This type of force is called frictional force. Generally, it resists the motion of the object when the surface of an object comes in contact with the surface of another object.
Applied Force: When a person or an object applies force on another object, which results in the movement of the object. It is called an applied force.
Normal Force: When an object is resting upon a surface, the surface exerts an upward force to balance the force exerted by the weight of the object. The upward force is known as the normal force which is applied by the surface.
Non-Contact Force
Non-contact force is defined as a force that is exerted without making any contact. It is further classified into three forces. They are gravitational force and magnetic force.
Gravitational Force: The attraction between any two objects with mass is known as gravitational force. It is a natural phenomenon. Stars, planets, and galaxies have an attractive force acting between them all the time. On Earth, physical objects possess weight due to gravity and the ocean tides occur due to the Moon's gravity.
Magnetic Force: A magnetic force is defined as a force exerted between two poles of a magnet and also between electrically charged moving particles. It can be either attractive or repulsive.
Did You Know?
It is assumed often that if an object is at rest, no force is acting on it. But, this is not true. When an object is at rest, there are two forces that act simultaneously on it. One is the gravitational force which acts downwards and the other one is the normal force which acts upwards. These two forces balance each other. Hence, the net force acting on the ball is zero. Now, if the ball is kicked, then only it will move from its stationary position because an external force greater than the other two forces is applied to it now. Hence, it will move in a particular direction.
So, this was all about pushing and pulling along with the types of forces. Now, let us assume that your mother asked you to pull heavy luggage from one cart and put them into another cart in the first case. In another situation, she just asks you to drag the luggage, which one would you prefer the easier task? Well, dragging is easier. Here, dragging is a push force, on the other hand, taking out luggage from one cart to another is a pulling force. This is the reason we say that pushing is better than pulling.
FAQs on Force Push and Pull
1. What is a force in Physics, and how are 'push' and 'pull' related to it?
In Physics, a force is an interaction that, when unopposed, changes the motion of an object. Essentially, every force is either a push or a pull. A push is a force directed away from the source, while a pull is a force directed towards the source. It can make an object start moving, stop moving, or change its direction or shape. Since force has both magnitude (strength) and direction, it is a vector quantity. Its S.I. unit is the Newton (N).
2. What are some common examples of push and pull forces in daily life?
We use push and pull forces constantly in our daily activities. Here are a few examples:
- Push Force Examples: Kicking a football, pushing a shopping trolley, closing a door, or pressing a switch.
- Pull Force Examples: Opening a drawer, pulling a bucket of water from a well, plucking the strings of a guitar, or pulling open a curtain.
3. Why is force considered a vector quantity?
Force is considered a vector quantity because its effect depends on both its magnitude (how strong the force is) and its direction (which way it is applied). Simply stating the strength of the force is not enough. For example, applying a 5 Newton force to a door will have a different result depending on whether you push it forward, pull it backward, or lift it upward. The direction is essential to describe the force completely.
4. What are the main effects a force can have on an object?
Applying a force to an object can result in several changes. The primary effects are:
- It can make a stationary object move.
- It can stop a moving object or slow it down.
- It can change the direction of motion of a moving object.
- It can change the speed of a moving object (either increase or decrease it).
- It can change the shape or size of an object (e.g., squeezing a sponge).
5. What is the difference between contact and non-contact forces?
The main difference lies in whether the objects need to touch for the force to act. Contact forces require physical contact between two objects. Examples include the muscular force used to lift a book or the frictional force that slows a rolling ball. In contrast, non-contact forces can act over a distance without any physical touching. Examples include the gravitational force pulling an apple to the ground or the magnetic force between two magnets.
6. Can an object be at rest if forces are acting on it? Explain with an example.
Yes, an object can be at rest even when multiple forces are acting on it. This happens when the forces are balanced. For example, a book resting on a table has two main forces acting on it: the gravitational force pulling it downwards and the normal force from the table pushing it upwards. These two forces are equal in magnitude and opposite in direction. They cancel each other out, resulting in a net force of zero, so the book remains stationary.
7. What are the different types of contact and non-contact forces mentioned in the CBSE syllabus?
As per the CBSE syllabus, forces are broadly classified into two categories, each with specific types:
- Contact Forces: These forces act only when objects are in direct contact.
- Muscular Force: The force resulting from the action of muscles, used for activities like walking, lifting, and pushing.
- Frictional Force: The force that opposes motion when two surfaces are in contact.
- Non-Contact Forces: These forces can act from a distance.
- Magnetic Force: The force exerted by magnets on magnetic materials like iron.
- Electrostatic Force: The force exerted by a charged body on another charged or uncharged body.
- Gravitational Force: The force of attraction that exists between any two objects with mass.
8. How does the concept of force explain why a ball rolling on the ground eventually stops?
A ball rolling on the ground stops because of an unbalanced contact force called friction. Even though no one is actively trying to stop it, the surface of the ground exerts a frictional force on the surface of the ball. This frictional force always acts in the direction opposite to the motion. It continuously opposes the ball's movement, causing it to slow down and eventually come to a complete stop.
