Adramatic demonstration, called "singing rods," involves a long, slender aluminum rod held in the hand near the rod's midpoint. the rod is stroked with the other hand. with a little practice, the rod can be made to "sing," or emit a clear, loud, ringing sound.

The spring has a spring constant of 1.00 * 10^3 N/m and the mass has been displaced 20.0 cm then the restoring force is 20000 N/m.

Explanation:

When a spring is stretched or compressed its length changes by an amount x from its equilibrium length then the restoring force is exerted.

spring constant is k = 1.00 * 10^3 N/m

mass is x = 20.0 cm

According to Hooke's law, To find restoring force,

    F = - kx

        = - 1.00 *10 ^3 * 20.0

     F = 20000 N/m

Thus, the spring has a spring constant of 1.00 * 10^3 N/m and the mass has been displaced 20.0 cm then the restoring force is 20000 N/m.