College Physics with MasteringPhysics 7th Edition by Jerry Wilson,Anthony Buffa,Bo Lou

Exercise 110

A spherical navigation buoy is tethered to the lake floor by a vertical cable (Fig.). The outside diameter of the buoy is 1.00 m. The interior of the buoy consists of an aluminum shell 1.0 cm thick, and the rest is solid plastic. The density of aluminum is 2700 kg/m 3 and the density of the plastic is 200 kg/m 3.
The buoy is set to float exactly halfway out of the water. Determine the tension in the cable.

FIGURE It's a buoy See Exercise.