physics definitions Flashcards
state Newton’s first 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
describe inertia
the property of an object that causes it to resist a change in its state of rest or uniform motion
state newton’s second 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, a, is directly proportional to the net force and inversely proportional to the mass
state newtons third law
when object A exerts a force on object B, object B simultaneously exerts an oppositely directed force of equal magnitude on object B
state newton’s law of gravity
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
state 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 distance between the charges
define magnetic flux linkage
the product of the number of turns on the coil and the flux through the coil
state faradays law
the emf induced is directly proportional to the rate of change of magnetic flux (flux linkage)
state 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
define emf
the total energy supplied per coulomb of charge by the cell
state Ohm’s law
current through a conductor is directly proportional to the potential difference across the conductor at constant temperature
state the work energy theorum
work done by a net force on an object is equal to the change in the kinetic energy of the object
define power
the rate of change at which work is done
define work
the product of the displacement and the component of the force parallel to the displacement
state the conversation of energy
the total energy in a system cannot be created nor destroyed, only transformed from one form to another
state the law of conservation of linear momentum
the total linear momentum of an isolated system remains constant
define weight
the gravitational force the earth exerts on any object on or near its surface
define normal force
the perpendicular force exerted by a surface on a object contact with it
vector
physical quantity that has both magnitude and direction
displacement
a change in position
speed
the rate of change of distance
velocity
the rate of change of displacement
acceleration
the rate of change of velocity
frictional force
the force that opposes the motion of an object
linear momentum
the product of the mass and velocity of an object
newtons second law in terms of momentum
the net force acting on an object is equal to the rate of change of momentum
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
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
principle of conservation of mechanical energy
in the absence of air resistance or any external forces, the mechanical energy of an object is constant
gravitational field
the force acting per unit mass
potential difference
the work done per unit positive charge
current
the rate of flow of charge
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 needed to emit an electron from the surface of a metal
