Definitions Flashcards
random errors
Random errors are errors of measurements in which the measured quantities differ from the mean value with different magnitudes and directions.
systematic errors
Systematic errors are errors of measurements in which the measured quantities are displaced from the true value by fixed magnitude and in the same direction.
Accuracy
Accuracy is a measure of how close the results of an experiment agree with the true value.
Precision
_______ is a measure of how close the results of an experiment agree with each other.
Internal energy
The internal energy is a function of state and the total microscopic kinetic and potential energies of the particles composing the system.
Specific latent heat of fusion
The specific latent heat of fusion, Lf , is defined as the amount of heat required per unit mass to change a substance from the solid phase to the liquid phase without any change in temperature
Specific latent heat of vaporisation
Specific latent heat of vaporisation is defined as the amount of heat required per unit mass to change a substance from the liquid phase to the vapour phase without any change in temperature.
First law of thermodynamics
First law of thermodynamics state that internal energy is a function of state and the increase in internal energy is equal to the sum of the heat supplied to system and work done on system.
Speed
is the rate of change of distance travelled with respect to time.
VELOCITY
Velocity is the rate of change of its displacement with respect to time.
Acceleration
Acceleration of an object is the rate of change of its velocity with respect to time.
normal contact force
Normal contact force is a force perpendicular to the surface experienced by a body when it is in physical contact with something else.
Hooke’s Law
Hooke’s Law states that within the limit of proportionality, the extension produced in a material is directly proportional to the load applied.
The principle of moments
The principle of moments states that, when an object is in equilibrium, the sum of anticlockwise moments about any point equals the sum of clockwise moments about the same point.
Moment
The moment of a force is the product of the force and the perpendicular distance between the axis of rotation and the line of action of the force.
Couple
A couple is a pair of forces, equal in magnitude but opposite in direction, whose lines of motion do not coincide.
Torque
The moment of a couple
Centre of gravity
Centre of gravity is the point on an object through which the entire weight of the object may be considered to act.
Stability
Stability of an object refers to its ability to return to its original position after it has been displaced from that position.
Pressure
Pressure is force acting per unit area.
Upthrust
Upthrust/buoyancy force is an upward force on a body produced by the surrounding fluid (i.e., a liquid or a gas) in which it is fully or partially immersed, due to the pressure difference of the fluid between the top and bottom of the object.
Archimedes’ principle
Archimedes’ Principle states that the upthrust experienced by an object partially or entirely immersed in a fluid is equal to the weight of the fluid displaced by the object.
Newton’s first law of motion
Newton’s first law of motion states that a body will continue in its state of rest or uniform motion in a straight line unless an external resultant force acts on it.
Newton’s second law of motion
Newton’s second law states that the rate of change of momentum of a body is proportional to the resultant force acting on it and the change takes place in the direction of the force.
Newton’s third law
Newton’s third law states that: If body A exerts a force on body B, then body B exerts a force of equal magnitude but in the opposite direction on body A.
Conservation of momentum
The principle of conservation of momentum states that the total momentum of a system of objects remains constant provided no resultant external force acts on the system.
Work
Work is the mechanical transfer of energy to a system or from a system by an external force on it.
Heat
Heatis the non-mechanical transfer of energy from the environment to the system or from the
system to the environment because of a temperature difference between the two.
The principle of conservation of energy
The principle of conservation of energy states that energy cannot be created nor destroyed in any process
Gravitational potential energy (uniform)
Gravitational Potential Energy is defined as the amount of work done in order to raise the body to the height h from a reference level.
Power
Power is defined as the rate of work done or energy converted with respect to time.
Angular displacement
θ is the angle subtended at centre of a circle by an arc of equal length to
the radius.
Angular velocity
Angular velocity, ω is the rate of change of angular displacement with respect to time.
Period
The period T of an object in circular motion is the time taken for the object to make one complete revolution.
Frequency (circular)
The frequency f of an object in circular motion is the number of revolutions made by the object per unit time.
Displacement
Displacement is the distance moved by the particle from its equilibrium position.
amplitude
The amplitude of a wave is the maximum displacement of the particle from its equilibrium position.
wavelength
The wavelength is the distance between 2 successive points on a wave which are in phase with one another.
period (waves)
The period is the time taken for a particle on the wave to complete one oscillation.