PHYSICS Force and Pressure CHAPTER 11
P1- Pressure is the force normal to a surface ÷ area of the surface.
P2- A liquid flows until the pressure along the same horizontal level is constant.
P3- Atmospheric pressure decreases with higher altitude because there is less air above a given altitude than there is at a lower altitude.
P1- Pressure = F ÷ A
P1- The unit of pressure is the pascal (Pa), which is equal to 1 N/m2.
P2- The pressure in a liquid increases with increasing liquid depth.
P3- Air molecules collide with surfaces and create pressure on them.
P1- The force F or A can be calculated by rearrainging the pressure equation P=F÷A to give F=pA or A=F÷P.
PRESSURE AND SURFACES
P2- The greater the density of a liquid, the greater the pressure in the liquid.
P2- The pressure P is due to the column of height H of liquid of density P is given by the equation P=h x p x g
PRESSURE IN A LIQUID AT REST
P3- The density of the atmosphere decreases with increasing altitude.
P3- The force on a flat object due to a pressure difference = the pressure difference x the area of the flat surface.
ATMOSPHERIC PRESSURE
P4- The upthrust on an object in a fluid: Is an upward force on the object due to the fluid. AND... Is caused by the pressure of the fluid.
UPTHRUST AND FLOTATION
P4- An object sinks if it's weight is greater than the upthrust on it when it is fully immersed.
P4- The pressure at a point in a fluid depends on the density of the density of the fluid and the depth of the fluid at that point.