A30-cm long string, with one end clamped and the other free to move transversely, is vibrating in its second harmonic. the wavelength of the constituent traveling waves is:

ill do it for 100, also this isnt 80 its 40

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.