F4 List of Definitions 2021 Flashcards
Physical quantity
A quantity that can be measured
Base quantity
A physical quantity that cannot be derived from another physical quantity
Derived quantity
A quantity which can be obtained by combination of base quantities by
mean of multiplication, division or both
Scalar quantity
Physical quantities that have magnitude only
Vector quantity
Physical quantities that have both magnitude and direction
Linear motion
Motion in a straight line
Speed, v
Rate of change of distance
Velocity, v
Rate of change of displacement
Acceleration, a
Rate of change of velocity
Free fall motion
A situation where an object falls down due to gravitational force only
Inertia
Tendency of an object to remain at rest or to continue its uniform motion in a straight line at uniform velocity
Newton’s first law of
motion
An object will remain at rest or move at uniform velocity unless acted upon by an external foce
Momentum, p
A product of mass multiplies by velocity
Force, F
The action of pushing or pulling to change the size and direction of motion
of an object
Newton’s second law of
motion
Rate of change of momentum is directly proportional to the force and
acts in the direction of the applied force
Impulsive Force, F
Rate of change of momentum in a collison or impact in a short period of
time
Impulse, J
Change of momentum
Newton’s third law of
motion
For every action there is a reaction of equal magnitude but in the opposite
direction
Weight, W
A gravitational force acting on an object
Newton’s universal law
of gravitation
The gravitational foce between two bodies is directly proportional to the
product of the masses of both bodies and inversely proportional to the
square of the distance between the centres of the two bodies
Centripetal force
A force acts on the body in a direction towards the centre of the circle
Kepler’s first law
All planets move in elliptical orbits with the Sun at one focus (Law of
Orbits)
Kepler’s second law
A line that connects a planet to the Sun sweeps out the equal areas in
equal times (Law of Areas)
Kepler’s third law
The square of the orbital period of any planet is directly proportional to
the cube of the radius of its orbit (Law of Periods)
Orbital radius
Average value of the distance between the planet and the Sun
Escape velocity, v
Minimum velocity needed by an object on the surface of the Earth to
overcome the gravitational force and escape to outer space
Temperature, T
Measure of the degree of hotness of an object
Heat, Q
The amount of thermal energy that can be transferred from one object to
another
Thermal equilibrium
A condition where net heat transfer between two objects becomes zero
Heat capacity, C
Quantity of heat needed to raise temperature of the object by 1°C
Specific heat capacity, c
Quantity of heat needed to raise the temperature of 1kg mass of the
substance by 1°C