Equation Notation Question

[tomc]

Hi,

 

I have been viewing some physics lecture videos and have come across a notation that is not familiar. Any help will be appreciated.

 

The following is part of an equation for wave motion:

ε(epsilon) φ(phi -with 2 dots above it) = c^2÷ε [(φ sub i - φ sub i+1)+(φ sub i - φ sub i-1)]

 

φ(phi with a dot above it) and φ(with 2 dots above it) What do the dots above φ indicate?

 

Thanks,

 

Tom

[D H]

Anything with two dots above it means the second time derivative of the thing in question. In this case, the thing in question is some function phi, typically used to indicate some kind of potential energy.

[tomc]

Hi,

 

Thank you, DH, for your response. The dots make sense now. You are right on - it was the second derivative for the potential energy of a spring.

 

Tom