Cheatography

# Gravitation Cheat Sheet (DRAFT) by Ayesha Talib

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
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
WM = 1/6 WE

### 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.