PROPERTIES OF MATTER

Stress = Restoring force/Area

Young’s modulus =,   where    F is restoring force,

                                                            A is area of cross-section,

                                                            L is the original length,

                                                             is the change in length           

Pressure is force (F) per unit area (A)

P=F/A

 

Poiseuille’s formula: The volume of a liquid flowing out per second through a horizontal capillary tube of length l, radius r, under a pressure difference p applied across its ends is given by

            Q =  =,  is coefficient of viscosity       

 

Stoke’s law: The backward viscous force acting on a small spherical body of radius r moving with uniform velocity v through fluid of viscosity  is given by

F=6   rv

 

Equation of continuity

A v = constant   where A is area of cross-section and v is the fluid velocity

 

Bernoulli’s principle: The sum of pressure energy, kinetic energy and potential energy per unit volume of an incompressible, non-viscous fluid in a streamlined flow remains constant.

P+1/2  v²+  gh= constant, where      P is pressure

 is the density of fluid

v is the fluid velocity

h is the height wrt some reference point

           

                                                  HEAT

Heat gained or lost by a body of mass when its temperature is changed by T is

 Q = mcT, where c is the specific heat of the material of the body

 

 Heat capacity = mc

 

Change of state

The amount of heat required to change the state of a substance of mass m without a change in temperature is

Q = m L, where L is the latent heat.