Railway Science (Physics-Force and Pressure)

The machine consists of mainly two parts i.e. static and rotating, these rotating parts heat up because of friction, and in this duration, if the leakage of oil happens it may catch fire. Static parts in some of the machines consist of wire and switch, if the oil leakage happens in these parts because of the short circuit, there may be a possibility of catching fire. To reduce friction lubricants grease is used. These lubricants smoothen the surface.

Friction is the force that opposes the motion of a solid object over another. There are mainly four types of friction - Static, sliding, rolling, and fluid. The frictional force exerted by fluids is also called drag. Lubricants prevent wear by reducing friction between two parts.

Lubricants are substances that help to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. Main functions of a lubricant - Preventing machine wear, corrosion protection, cooling by dissipating heat from surfaces.

It is a force without which a body cannot move in a circular orbit. It depends on the mass, velocity of the object and radius of the circle in which it moves. Examples - Gravitational force keeping a satellite in orbit. Centrifugal force - It is the apparent force that is felt by an object moving in a curved path that acts outwardly away from the centre of rotation. Examples - Vehicle driving round a curve. Mechanical force - It is a force between two objects which require direct contact with each other. Examples - Push a door. Frictional force - It is the force generated by two surfaces that contact and slide against each other. Examples - Rubbing hands, dragging a chair.

Types of Friction and their examples: Static Friction - When you hit a tennis ball. Sliding friction - When an ice skater is skating. Rolling friction - When a soccer ball rolls. Air friction - A sky diver falling out of the air. Fluid friction - When a swimmer swims the water and the swimmer's body rub together. Frictional force can be reduced in the following ways - Use of lubricants, polishing, streamlining, ball bearings.

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction: Static friction acts on objects when they are resting on a surface. Examples: Rock on the floor, A vehicle rested on a hill. Sliding friction is friction that acts on objects when they are sliding over a surface. Examples: Rubbing the hands together generates heat due to friction. Rolling friction is friction that acts on objects when they are rolling over a surface. Example - Soccer ball rolls along the ground. Static friction > sliding friction > rolling friction.

Frictional force - The force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Fluids - The substances that flow easily because of increased intermolecular spaces and do not have a fixed shape. The frictional force on an object moving through a fluid is called drag force, and it is proportional to the velocity of the object relative to the fluid, the viscosity of the fluid, and the shape of the object.

Friction is the force that resists motion when the surface of one object comes in contact with the surface of another. There are mainly four types of friction: static friction, sliding friction, rolling friction, and fluid friction.

Rolling friction is the resistive force offered by any surface which opposes the rolling motion of any object that rolls over it, thus causing it to slow down and eventually stop. Rolling friction is generated when a round or a spherical object rolls across a surface. Examples - Wheels of vehicles, Soccer ball, Driving on a wet floor, rolling of a pen without a cap, Wheels of skateboard.

Friction can be increased by - Making the surfaces rough, pressing the surfaces harder against each other, removing the lubrication between the surfaces in contact, using sliding motion rather than rolling motion, increasing the surface area in contact. Friction can be reduced by - Lubricating the surfaces, use of ball bearings (i.e. replacing sliding friction with rolling friction), streamlining the body.