Railway Science (Physics-Force and Pressure)

Archimedes’ principle is a law of physics fundamental to fluid mechanics. Beer-Lambert law states that the concentration of the sample and path length is directly proportional to the absorbance of the light. Pascal's law states that the external static pressure applied on a confined liquid is distributed or transmitted evenly throughout the liquid in all directions. Bernoulli’s Principle states that as the speed of a moving fluid increases (liquid or gas), the pressure within the fluid decreases.

Boyle's law. Graham's Gas Diffusion Law - The rate of diffusion of a gas at constant pressure is inversely proportional to the square root of its molar mass. Charles's law - The volume of an ideal gas is directly proportional to the absolute temperature at constant pressure. Gay-Lussac's law - The pressure of a given mass of gas varies directly with the absolute temperature of the gas when the volume is kept constant.

According to this law, if a body is at rest, it will remain at rest or if a body is moving in a straight line with a uniform velocity, then it will remain in motion. Unless an external force is applied to that body.

Newton's Second law of Motion - The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts. Newton's First Law of Motion - An object remains at rest, or moves at a constant speed in a straight line, unless a force is applied to it. Newton's Third Law of Motion - For every action, there is an equal and opposite reaction.

Newton’s Third Law of motion: For every action, there is an equal and opposite reaction. Newton First Law of motion: Every object will remain at rest or in uniform motion in a straight line unless an external or an unbalanced force acts upon it.

SI unit - Newton, F = m (mass) × a (acceleration), a vector quantity, Spring balance:- Hooke's Law, which states that the force needed to extend a spring is proportional to the distance that spring is extended from its rest position. Momentum (p):- SI unit: (kg⋅m/s), p = m (mass) × v (velocity), a vector quantity. Velocity (V):- It is the rate of change of distance. SI unit:- m/s. Mass (m) :- SI unit :- kg, Mass = ρ (density) × v (volume), a scalar quantity.

Rolling friction is a type of kinetic friction; it comes into play when one body actually rolls on the surface of another body. Static > Sliding > Rolling. Static frictional force is the strongest form among all. Fluid friction is friction that acts on objects that are moving through a fluid. Friction is the force that resists motion when the surface of one object comes in contact with the surface of another.

Scalar quantities are described only by a magnitude. Example - Distance, Speed, Mass, Temperature, Energy, Work, Volume, Area. Vector quantities are defined as the physical quantity that has both directions as well as magnitude. Example - Torque, displacement, velocity.

It is the force of attraction between all masses in the universe. An electric force is the interaction of either attractive force or repulsive force between two charged bodies. Buoyant force is a force acting on an object opposite to gravity by fluid which is being submerged partially or completely in fluid. Nuclear forces are the forces that act between two or more nucleons.

Kepler's laws of planetary motion are three laws that describe the motion of planets around the Sun. Law of Orbits - All planets move in elliptical orbits, with the Sun at one focus. Law of Areas - A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. Law of Periods - The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit.