A wave travels along a plastic slinky with a wavelength of 5.0 × 10^1 m and a speed of 4.2 m/s.

Question

A wave travels along a plastic slinky with a wavelength of 5.0 × 10^1 m and a speed of 4.2 m/s. Once the wave reaches the end of the plastic slinky, it continues along a heavier metal slinky. Calculate the wavelength in the second slinky if the wave travels at 1.0 m/

Answer 1

As the wave moves from one medium to another, in this case the plastic to metal slinky the frequency does not change which is important. we then can use: ν = fλ.

In our case f is constant such that we can set v1/λ1=v2/λ2. Where v2 is the velocity of the wave moving through the metal slinky. And we are calculating for λ2.

So λ2= (v2*λ1)/v1= (1 m/s *50 m)/ 4.2 m/s = 11.9 m/s ≈ 12 m/s