QUOTE(infrasonic @ Jul 23 2013, 12:20 PM)
does the analisis works for you? are there any books like that for sejarah?
which part of air pressure your don't understand?
like which area has lower air pressure, and which one has higher pressure. just dont understand which part has more, which part has less
yeah, they have Sejarah, Geo, Science and Maths in the series
QUOTE(Krevaki @ Jul 23 2013, 04:37 PM)
Pressure is the normal force exerted by a fluid per unit area. Units commonly used include newton per square meter (N/m^2), pascal (Pa), standard atmosphere (atm), bar and kilogram-force per square centimeter (kgf/cm^2). Note that pascal is a very small unit and hence its multiple, the kilopascal is more commonly quoted. The true pressure at a given point is called the absolute pressure. It is calibrated against absolute vacuum. So vacuum would give a reading of 0 Pa and the atmosphere gives 101,325 Pa at sea level. If however, our measurement device is calibrated at atmospheric pressure, then it would give the difference between the measured absolute pressure and the atmospheric pressure. This pressure is called the gage pressure. When the absolute pressure is below atmospheric pressure, we take the difference to be positive and call it the vacuum pressure.
P_gage=P_abs-P_atm
P_vacuum=P_atm-P_abs
For a fluid at rest, the pressure does not change in the horizontal direction. However, the pressure increases with depth (i.e. the vertical direction), measured from the free surface of the fluid. P=rho*g*h, rho is the density of the fluid, g is gravitational acceleration and h is the depth, measured from the free surface of the fluid. For multi-fluid cases, P=summa(rho*g*h).
The barometer is the device used to measure atmospheric pressure. Imagine taking a large test tube, pumping out all the air and then inverting it into a trough of mercury. The mercury will be pushed up the test tube. In fact, the mercury gets pushed up by 760mm at atmospheric condition. For this reason, the unit is mmHg. In theory, our trough could be filled with any liquid. A less dense liquid gives a more sensitive reading, but will be raised to a higher level. For comparison, water goes up to 10.3m under atmospheric condition. The manometer operates based on the principles of the barometer. A common manometer consists of a U-tube filled with one or more liquids. Its two ends are connected to the two points where the pressure difference is to be measured. The difference is then shown as the height difference between the two arms of the tube. To help keep the size of the manometer down, heavier liquids are used.
this is too complicated, Form 3 hasnt gone THAT far lol