physics Term-mechanic

MECHANIC
Acceleration:	The rate of change of velocity with respect to time.
Acceleration due to gravity:	The acceleration imparted to bodies by the attractive force of the earth or any other heavenly body.
Amorphous:	Solids which have neither definite form nor structure.
Annihilation:	A process in which a particle and antiparticle combine and release their rest energies in other particles.
Bar:	A unit of pressure, equal to 105 Pascals.
Bernoulli's theorem:	The total energy per unit volume of a non-viscous, incompressible fluid in a streamline flow remains constant.
Boyle's law:	For a given mass of a gas at constant temperature, the volume of the gas is inversely proportional to the pressure.
Bulk's modulus of elasticity:	The ratio of normal stress to the volumetric strain produced in a body.
Buoyant force:	upward force on an object immersed in fluid.
Calorie:	A unit of heat, 1Calorie = 4.186 joules.
Capillarity:	The rise or fall of a liquid in a tube of very fine bore.
Centrifugal force:	An outward pseudo force acting on a body in circular motion.
Centripetal force:	The radial force required to keep an object moving in a circular path; it is equal to mv2/r.
Coulomb's law:	The force between any two charges is directly proportional to the product of charges and inversely proportional to the square of the distance between the charges.
Density:	The mass of a substance per unit volume.
Displacement:	The shortest distance between the initial and final position of a moving body. It is a vector quantity.
Distance:	The actual path length covered by a body. It is a scalar quantity.
Escape Velocity:	The minimum velocity with which an object must be thrown upwards so as to overcome the gravitational pull, it is equal to , where M is the mass of the planet and R is the radius of the planet.
Fluids:	Matter that has the ability to flow.
Gamma ray:	A high energy photon.
Graham's law of diffusion:	The rate of diffusion of a gas is inversely proportional to the square root of its density.
Gravitational constant (G):	The constant of proportionality in Newton's law of gravitation, G = 6.67 x 10-11 Nm2/kg2
Gravitational potential at a point:	The amount of work done against the gravitational forces to move a particle of unit mass from infinity to that point.
Gravitational potential energy:	The energy possessed by a body due to its position.
Gravity:	The gravitational attraction at the surface of a planet or other celestial body.
Hooke's law:	Within elastic limit, stress is directly proportional to strain.
Horsepower:	unit of power, 1H.P. = 746 Watts.
Impulse:	The product of force and time for which force acts, also equal to the change in momentum.
Inertia:	The property of a body to resist a change in its state of rest or of uniform motion.
Internal energy:	Sum of the kinetic energy and potential energy of all molecules of an object.
Joule:	The unit of work and energy, 1J = 1N-m.
Kinetic energy:	The energy possessed by a body due to its motion, it is equal to ½ mv2, where m is the mass and v is the speed of the body
Kepler's first law of planetary motion:	Each planet moves in an elliptical orbit, with the sun located at one of the foci.
Kepler's second law of planetary motion:	The radius vector joining the planet to the sun covers equal areas in equal intervals of time.
Kepler's third law of planetary motion:	The square of the period of a planet is directly proportional to the cube of the radius of the semi major axis of the orbit.
Law of Conservation of Energy:	Energy can neither be created nor destroyed, but can be transformed from one form to another.
Law of conservation of mass:	Mass can neither be created nor destroyed in a chemical reaction.
Law of conservation of momentum:	In the absence of external forces, the total momentum of a group of interacting objects remains constant.
Mechanical energy:	The sum of energy possessed by a body due to its position, configuration and motion.
Modulus of rigidity:	The ratio of tangential stress to the shear strain produced in a body.
Momentum:	The product of mass and velocity of a body, it is a measure of the quantity of motion in a body.
Natural frequency:	The frequency, with which a system oscillates in the absence of external forces, it depends on the size, composition, and shape of the object.
Newton:	The unit of force, equal to the force that will produce an acceleration of 1m/s2 in a body of mass1 kg.
Newton's first law of motion:	A body continues in a state of rest or of uniform motion in a straight line unless it is acted upon by an external (unbalanced) force.
Newton's law of gravitation:	The gravitational force of attraction acting between any two particles is directly proportional to the product of their masses, and inversely proportional to the square of the distance between them. The force of attraction acts along the line joining the two particles.
Newton's second law of motion:	The rate of change of momentum is directly proportional to the force applied.
Newton's third law of motion:	To every action there is an equal and opposite reaction.
Oscillatory motion:	The to and fro motion of a body about its mean position.
Pascal:	A unit of pressure, equal to the pressure resulting from a force of 1 Newton acting uniformly over an area of 1m2.
Pascal's law:	The pressure exerted on a liquid is transmitted equally in all directions.
Plasticity:	The property of a solid whereby it undergoes a permanent change in shape or size when subjected to a stress.
Potential Energy:	The energy possessed by a body by virtue of its position or configuration.
Projectile:	An object which after being given an initial velocity is allowed to fall under the effect of gravity alone.
Rectilinear Motion:	The motion of a body in a straight line.
Restoring force:	The force which tends to bring an oscillating body towards its mean position whenever it is displaced from the mean position.
Resultant Force:	A single force, which acts on a body to produce the same effect in it as, done by all other forces collectively.
Rigid body:	An idealized extended body whose size and shape is fixed and remains unaltered when forces are applied.
Scalar Quantity:	A physical quantity, which is described completely by its magnitude.
Second's Pendulum:	A simple pendulum whose time period on the surface of earth is 2 seconds.
Shear strain:	The ratio of the relative displacements of one plane to its distance from the fixed plane.
Shear stress:	The restoring force developed per unit area when deforming force acts tangentially to the surface of body producing change in the shape of the body without any change in volume.
Speed:	The distance traveled by a body per unit of time.
Simple harmonic motion:	The vibratory motion that occurs when the restoring force is proportional to the displacement from mean position and is directed opposite to the displacement.
Surface tension:	The property of a liquid due to which its surface behaves like a stretched membrane.
Uniform Circular Motion:	The motion of an object in a circular path with uniform speed.
Van der Wall's force:	General term for weak attractive intermolecular forces
Vector Quantity:	A quantity, which needs both magnitude and direction to describe it.
Velocity:	Distance traveled by a body in a particular direction per unit time or the displacement of the body per unit time. It is a vector quantity.
Weight:	The force with which a body is attracted towards the center of the earth. The weight of a body of mass m is given by mg, where g is the acceleration due to gravity.
Weightlessness:	The state when the apparent weight of a body becomes zero.
Work:	Work is done when force acting on a body displaces it. Work = Force x Displacement in the direction of the force.
Young's modulus of elasticity:	The ratio of normal stress to the longitudinal strain produced in a body.