Definitions Flashcards
Vector
A physical quantity that has both direction and magnitude
Scalar
A physical quantity that has only magnitude
Resultant vector
The single vector which has the same effect as the original vectors acting together
Distance
Length of path travelled
Displacement
Change in position
Speed
Rate of change of distance
Velocity
Rate of change of displacement
Acceleration
Rate of change of velocity
Weight
The gravitational force that the earth exerts on any object on or near its surface
Normal force
The perpendicular force exerted by a surface on an object in contact with ut
Frictional force
The force that opposes the motion of an object and acts parallel to the surface with which the object is in contact
Newtons first Law
An object continues in a state of rest or uniform velocity unless acted upon by a net or resultant force
Inertia
The property of an object that causes it to resist a change in its state of rest or uniform motion
Newtons second Law
When a net force is applied to an object of mass, it accelerates in the direction of the net force. The acceleration is directly proportional to the net for and inversely proportional to the mass
Newtons third Law
When object A exerts a force on object B, object B simultaneously exerts a force of equal magnitude on object A
Linear momentum
The product of mass and velocity of the object
Elastic collision
A collision in which both momentum and kinetic energy is conserved
Inelastic collision
A collision in which only momentum is conserved
Impulse
The product of the net force and the contact time
Work done on an object by a force
The product of the displacement and the component of force parallel to the displacement
Gravitational potential energy
The energy an object possesses due to its position relative to a reference point
Kinetic energy
The energy an object has a result of the objects motion
Mechanical energy
The sum of gravitational potential and kinetic energy at a point
Work energy theorem
The work done by a net force on an object is equal to the change in the kinetic energy of the object
Power
The rate at which work is done
One watt
The power when one joule of work is done in one second
Efficiency
The ratio of output power to input power
Newtons law of Universal Gravitation
Every particle with mass in the universe attracts every other particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers
Gravitational field
The force acting per unit mass
Coulomb’s Law
Two point charges in free space or air exert forces on each other. The force is directly proportional to the product of the charges and inversely proportional to the square of the distance between the charges.
Magnitude of the electric field at a point
The force per unit positive charge
Potential difference
The work done per unit positive charge
Current
The rate of flow of charge
Ohm’s Law
Current through a conductor is directly proportional to the potential difference across the conductor at constant temperature
Resistance
A materials opposition to the flow of electric current
EMF
The total energy supplied per coulomb of charge by the cell
Magnetic flux linkage
The product of the number of turns on the coil and the flux through the coil
Faraday’s Law of electromagnetic induction
The emf induced is directly proportional to the rate of change of magnetic flux
Lenz’s Law
The induced current flows in a direction so as to set up a magnetic field to oppose the change in magnetic flux
Diode
A component that only allows current to flow in one direction
Threshold frequency
The minimum frequency of incident radiation at which electrons will be emitted from a particular metal
Work function
The minimum amount of energy required to emit an electron from the surface of a metal and know that the work function is material specific
