This is a draft cheat sheet. It is a work in progress and is not finished yet.
UNIVERSAL LAW OF GRAVITATION
every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of the distance b/w them.
6.673.10-11Nm2kg-2; Henry Cavendish using a sensitive balance. |
IMPORTANCE
force that binds us to earth; motion of moon around earth; motion of planets around sun; tides due to moon and sun. |
ACCELERATION DUE TO GRAVITY
acceleration experienced by a freely falling object towards the centre of the earth. 9.8 m/s2.
ER>PR = Eg<Pg |
free fall: it is the object falling towards the earth under the influence of attraction force earth/gravity.
MASS /\ WEIGHT
quantity/amount of matter present in an object |
force by which earth attracts an object |
scalar quantity |
vector quantity |
SI unit: kg |
SI unit: N |
remains constant everywhere |
changes as gravity changes |
can never be 0 |
0 at the centre of earth |
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CELESTIAL BODIES: MASS & RADIUS
earth |
5.98.1024kg |
6.37.106m |
moon |
7.36.1022kg |
1.74.106m |
THRUST
force acting on an object perpendicular to the surface. |
PRESSURE
thrust on unit area. SI unit: Pa or N/m2 |
BUOYANT FORCE OR UPTHRUST
tendency of fluids to exert upward force on an immersed object.
factors affecting buoyant force
volume of the object immersed in fluid
density of fluid
acceleration due to gravity
temperature of fluidinversely proportional
FLOAT:
upthrust > weight of object
dfluid > dobject
SINK:
upthrust < weight of object
dfluid < dobject |
density of substance is the mass per unit volume.
ARCHIMEDES' PRINCIPLE
when a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it. used in designing submarines & ships, lactometers & hydrometers. |
lactometers: determine the purity if a sample of milk.
hydrometers: determine the density of liquids.
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