What energy density represents. Derive it mathematically.

What electron volt represents.

What is strain energy state it mathematically.

Population density is represented by

What is non-uniform velocity?how one expresses instantaneous velocity mathematically?

What is a bar pendulum ? Express time period mathematically.

What are different moduli of elasticity. Derive mathematical relation between them. Define poisson's ratio and prove that the limit lies between -1 to 1/2.