a. An external longitudinal force F = F cosωt acts on an infinite rod at some
0
cross section. What waves of velocity and deformation occur in the rod? The
cross section of the rod is S, its material density is ρ, and the wave velocity in
the rod is c.
b. An external longitudinal force F = F cosωt acts in two cross sections of an
1 0
infinite rod located at distance l from each other. What waves arise in the rod?
At what values of l is the power of the wave in the rod the greatest? Why is the
energy of the resultant wave in the rod not equal to the sum of the energies
of the waves emitted by each source separately?