1. The problem statement, all variables and given/known data A uniform ball of radius r = 0,3m swim in the water so the half of the ball is in the water. What is the work W required to pull out the ball from the water. (You can assume that the density of the water is ρ = 1000 kg/m³, the acceleration of gravity g = 9,81 m/s², ignore air and fluid resistance). 2. Relevant equations - According to hydrostatic law and equilibrium's law the weight force G = mg is equal to lift force F = Vρg, V is volume of the ball inside the water, V =2/3r³π. G =2/3r³πρg . - Work W is W = ʃ[mg - ρg(πh²R - 1/3πh³)]dh, (h =0 to h = r) Expression πh²R - 1/3πh³ represent the volume of ball immersed in water during the process of pulling out the ball. 3. The attempt at a solution - W =7/12r³πρgr. W = 145,54J.