Basic Biomechanics 5th Edition by Susan Hall

Exercise 8

For all problems, assume that the specific weight of freshwater equals 9810 N/m 3 and the specific weight of seawater (saltwater) equals 10,070 N/m 3.
A beach ball weighing 1 N and with a volume of 0.03 m 3 is held submerged in seawater. How much force must be exerted vertically downward to hold the ball completely submerged? To hold the ball one-half submerged?