Pv = nrt, is the a. equation of state of an ideal gas
b. theorem of equipartition of energy
c. second law of thermodynamics

Ideal gas law:

PV = nRT

P = pressure, V = volume, n = # of moles, R = gas constant, T = temperature

Equipartition theorem:

Each degree of freedom that a molecule has adds 0.5kT to its total internal energy where k = Boltzmann's constant and T = temperature

2nd law of thermodynamics:

A set of governing principles that restrict the direction of net heat flow (always hot to cold, heat engines are never 100% efficient, entropy always tends to increase, etc)

Clearly the answer is Choice A

v=ir = 3x15 =45 v

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.