SAGS Flashcards
Vector
A physical quantity that has both magnitude and direction.
Scalar quantity
A physical quantity that has magnitude only.
Resultant vector
The single vector which has the same effect as the original vectors acting
together.
Distance
The length of path travelled (scalar quantity).
Displacement
A change in position (vector quantity).
Speed
The rate of change of distance (scalar quantity).
Velocity
The rate of change of position / The rate of change of displacement / The rate of
displacement (vector quantity).
Acceleration
The rate of change of velocity (vector quantity).
Weight
The gravitational force 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 it.
Frictional force
The force that opposes the motion of an object.
Gravitational field
Description: A region in space where a mass will experience a force.
Def: A force acting per unit mass
Newton’s 1st law
An object continues in a state of rest or uniform (moving with constant) velocity
unless it is acted upon by a net or resultant force.
Newton’s 2nd law
When a net force, Fnet, is applied to an object of mass, m, it accelerates in the
direction of the net force. The acceleration is directly proportional to the net
force and inversely proportional to the mass.
Newton’s 3rd law
When object A exerts a force on object B, object B simultaneously exerts an
oppositely directed force of equal magnitude on object A.
Newton’s 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 centres.
Gravitational potential
energy
The energy an object possesses due to its position relative to a reference
point.
Kinetic energy
The energy an object has as a result of the object’s motion.
Mechanical energy
The sum of gravitational potential and kinetic energy at a point.
The law of
conservation of
energy
The total energy in a system cannot be created nor destroyed, only transformed
from one form to another.
Principle of
conservation of
mechanical energy
In the absence of air resistance or any external forces, the mechanical energy of
an object is constant.
Power
The rate at which work is done OR the rate at which energy is transferred.
Efficiency
The ratio of output power to input power.
Coulomb’s law
Two point charges 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.
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
The current through a conductor is directly proportional to the potential
difference across the conductor at constant temperature.
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
(flux linkage).
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.
Inertia
The property of an object that causes it to resist a change in its state of rest or
uniform/constant motion.
Work done on an
object by a force
The product of the displacement and the component of the force parallel
to the displacement (scalar quantity).
Linear momentum
The product of the mass and velocity of the object (vector quantity).
Newton’s 2nd law in
terms of momentum
The net force acting on an object is equal to the rate of change of momentum.
Law of conservation
of linear momentum
The total linear momentum of an isolated system remains constant.
Elastic collision
A collision in which both momentum and kinetic energy are conserved.
Inelastic collision
A collision in which only momentum is conserved.
Impulse (J)
The product of the net force and the contact time.
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.
Diode
A component that only allows current to flow in one direction.
Photoelectric effect
The process that occurs when light shines on a metal and electrons are ejected.
Threshold frequency
(cut-off frequency)
The minimum frequency of incident radiation at which electrons will be emitted
from a particular metal.
Work function
The minimum amount of energy needed to emit an electron from the surface of
a metal (material specific).
