Res that branch of mechanics which deals with forces and their action on the motion of bodies.
Force: The agency which moves or tends to move, stops or tends to stop the motion of a body is called force. The force can also change the direction of motion of a body. Example: A door can be opened or closed by applying a force in the form of pushing and pulling.
The example of forces acting on us are the force of gravity acting downward, the force of friction which helps us to walk on the ground and many others.
There are two major types of forces.
1. Contact Forces
2. Non-contact Forces
1. Contact Forces: A contact force is a force that acts at the point of contact between two objects. Examles: i. Friction ii. Drag
2. Non-contact Forces: A non-contact force is defined as the force between two objects which are not in physical contact. Examles: i. Gravitational Force ii. Electrostatic Force
Contact: A contact force is a force acts at the point of contact between two objects. Applied forces (push, pull and twist) are contact forces.
Non-contact: A non-contact force is defined as the force between two objects which are not in physical contact.
It is the force that resists motion when the surface of one object comes in cond with the surface of another.
Drage force is the resistance force caused by the motion of a body through surrounding fluid. It acts opposite to the relative motion of any object moving with respect to
It is an upward force exerted by a liquid on an object immersed in it. When we try to immerse an object in water, we feel an upward force exerted on the object. This force increases as we push the object deeper into the water. A ship can float in the sea due to this force which balances the weight of the ship.
It is the force exerted by the surface on an object lying on it. This force acts outward and perpendicular to the surface. It is also called the support force upon the object.
It is the resistance (opposition) offered by air when an object falls through it.
It is the force experienced by a rope when a person or load pulls it.
It is a force that brings certain materials back to their original shape after being deformed. Examples are rubber bands, springs, trampoline etc.
The non-contact forces can work from a distance. That is why these are sometimes called as action-at-a-distance.
There is always a field linked with a non-contact force. Due to this property, non-contact forces are also called field forces.
When we throw an object upward, it is the graviational force of earth that brings it back to the Earth.
An object resting on a surface exerts a downward force called its weight.
An electrostatic force acts betwen two charged objects. The opposite charges attract each other and similar charges repel each other. Examples: Like gravitational force, electrostatic force is also a long-range force.
It is a force which a magnet exerts on other magnets and magnetic materials. Example: like iron, nickle and cobalt.
These are also non-contact forces acting between the subatomic particles.
There are four fundamental forces is nature. There are:
i. Gravitational force
ii. Electromagnetic force
iii. Strong nuclear force
iv. Weak nuclear force
Every force comes under any of these forces.
It is the force that These are long range forces. Electro-static and magnetic force come under this category. Electromagnetic forces are stronger forces, than gravitational and weak nucleat
A strong nuclear force is a short-range force. The strong nuclear force, is responsible to keep protons and neutrons together inside the nucleus. Range of this force is of the order of 10-14m.
Weak nuclear force is responsible for the disintegration of a nucleus. For example, the weak nuclear force executes the B-decay (beta decay) of a neutron, in which a neutron transforms into a proton. In the process, a ẞ-particle (electron) and an uncharged particle called antineutrino are emitted. In other words, we can say that due to weak nuclear force radioactive decay of atoms occurs. However weak nuclear force is stronger than the gravitational force but weak than the electromagnetic force. It is a short-range force of the order 10-17m.
In the process, a β-particle (electron) and an uncharged particle called a neutrino.
At a very high tempertaure, the electromagnetic force and weak nucler force is unified as electro weak force.
A body continues its state of rest or of uniform motion in a straight line unless acted upon by some external force.
The property of a body to maintain its state of rest or uniform motion in a straight line is called inertia.
The characteristic of a body which determines the magnitude of acceleration produced when a certain force act upon it is known as mass of the body.
If a net external force acts upon a body, it accelerates the body in the direction of force. The magnitude of acceleration is directly proportional to the magnitude of force and is inversely proportional to the mass of the body.
Onge newton is the force which produces an acceleration of Ims-2 in a body of mas
For evere activisties velocitways an equal and opposite reaction.
The prob to that of Thesith the motion of elementary particles having velocities close to that of light. These velocities are known as relatives velocities For example, mass of objects starts increasing, length of object appearing shorter and time duration of events becomes longer.
Mass: The characteristic of a body which determines the magnitude of acceleration produced when a certain force acts upon it is known as mass of the body. Mass is a scalar quantity denoted by 'm'. It reamins the same everywhere. Practically, mass is measured by an ordinary balance. The SI unit of mass is kilogram (kg).
Weight: The weight of an object is equal to the force with which the Earth attracts the body towards its centre. By Newton's law, F = ma, the weight of a body 'w' will be given by w = mg, where g is the gravitational acceleration. As the value of g varies from place to place and also with altitude, therefore, the value of weight does not remain the same everywhere.
Balance scales are commonly used to compare masses of objects or to weigh objects by balancing them with standard weights.
There is type of mechanical balances which are used to weigh heavy items like flour bags, cement bags, steel bars, etc. These are called mechanical plateform balances.
The force that opposes the motion of the moving object is called friction.
Long range force act over large distances without physical contact while short range force act only at very small distances typically with in atomic or subatomic scales.
i. Static friction
ii. Kinetic friction
Sliding friction: The resistance created by any two objects when sliding against each other.
Sliding friction can be divided into two categories.
i. Static friction
ii. Kinetic friction
When an object rolls over a surface, the friction produced is called rolling friction.
The highest velocity attained by an object falling through a fluid is called terminal
The following methods are used to reduce friction.
L The parts which slide against each other are highly polished.
Since, the friction of liquids is less than that of solid surfaces, therefore, oil or gases is applied between the moving part of machinery.
ii. As rolling friction is much less than the sliding friction, so sliding friction is converted into rolling friction by the use of ball bearing in the machines and wheels under the heavy objects.
iv. Frictional force does not act only among solids, high speed vehicles, aeroplanes and ships also face friction while moving through air or water. If the front of a vehicle is flat, it faces more resistance by air or water. Therefore, the bodies moving through air or water are streamlined to minimize air or water friction. The air passes smoothly over the slanting surface of vehicle. This type of flow of air is know as streamline flow. The vehicles designed from the front are said to be streamline.
The momentum of a moving body is the product of its mass and velocity. Like velocity momentum is also a vector quantity. The SI unit of momentum is kg ms, It can also be written as Ns.
Formula: pmxv
When a large force Facts on an object for a short interval of time, the impulse of the force is defined as the total change in momentum of the object.
The rate of change of momentum of a body is equal to the force acting on it. The direction of change in momentum is that of the force.
If no external force acts on an ioslated system, the final total momentum of the system is equal to the initial total momemtum of the system.
Contact: A contact force is a force that acts at the point of contact between two objects. Applied forces (push a pull and twist) are contact forces. Some other examples of contact forces are the following.
Examples:
i. Friction
ii. Drag
iii. Thrust
iv. Normal force
Non-Contact: A non-contact force is defined as the force between two objects which are not is physical contact. The non-contact forces can work from a distance That is why these are sometimes called as action-at-a-distance. There is always field linked with a non-contact force. Due to this property, non-contact forces are also called field forces. A few examples of non-contact forces are describe below.
Example: i. Gravitational force iii. Magnetic force
ii. Electrostatic force iv. Strong and weak nuclear forces
