Mini Review Exercise Solution

n  Clearly define the following

 

     ð  Internal energy of a system.

 

          Sum of the energies of all of the molecules

 

     ð  Isothermal process

 

          One that is carried out at constant temperature

 

     ð  Adiabatic process

 

          One in which no heat is allowed to flow into or out of the system

 

     ð  Isobaric process

 

          One in which the pressure is kept constant

 

n  Express work in terms of pressure and volume

 

      W = PDV

 

n  Write the first law of thermodynamics as an equation

 

      U = Q - W

 

n  In class I explained in detail why the metal pieces in the container separated when I rubbed a

     cylinder and touched a conductor to them.  Clearly provide that explanation below.

 

     If the rod was charged positive then that attracted the electrons and made the leaves positive and vice versa.

 

n  Why did the pieces eventually come back together after a time (without touching them)?

     Where did the charge go?

 

     Into water molecules in the air

 

n  The text states a use for an electroscope. What is that use?

 

     To detect electrical charge.

 

n  Write Coulomb's law below.

 

     F = kQ₁Q₂/r²

 

n  Coulomb's and Newton's Force law are similar. What is the major difference I discussed in

     class?

 

     Newton's is attractive, Coulomb's can be attractive or repulsive

 

n  Define temperature

 

     Average kinetic energy of individual molecules