A spider hangs from a strand of silk whose radius is 4.0 10-6 m. The density

Question:

A spider hangs from a strand of silk whose radius is 4.0 × 10-6 m. The density of the silk is 1300 kg/m3. When the spider moves, waves travel along the strand of silk at a speed of 280 m/s. Ignore the mass of the silk strand, and determine the mass of the spider.