Question

A transverse wave on a cord is given by D(x,t) = .45cos(2.6x + 1.2t) where D and x are in meters along with t in seconds. What is the displacement and velocity on the cord when t = 2 second and point x = 1.5m ? Any explanation on thought process would also be helpful, thanks.

Answer 1

The displacement is given by
  
Now at the point x = 1.5 m, at time t = 2 s, we get the displacement as
   
  
Velocity is
  
  
So, at the point x = 1.5 m, at time t = 2 s, we get the velocity as