Question

A chld is holding a ball with a diameter of 4.50 cm and average density of 0.0843 g/cm under water. Determine the force (In N) needed to hold it completely submerged. magnitude direction downward Need Help? Peadit

Answer 1

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NET UPWARD FORCE ACTING ONBALL F = F_r - w where F_r = p_wvg(Ruoyant Force) w = p_bvg(weight of ball) F = vg(p_w - p_b) v = 4/3pir^3 = 4/3(3.14)(0.0225)^3 v = 4.769 times 10^-5 m^3 p_b = 0.0843 g/cm^3 = 0.0843 times 10^-3kg/(10^-2)^3m^3 p_b = 84.3 kg/m^3 (Ball density) p_w = 1g/cm^3 = 1000 kg/m^3 Density of water Therefore F = (4.769 time s10^-5)(9.8)(100 - 84.3) F = 0.4274 N this is magnitudes of upward Force Acting on Ball Hence child need 0.4279N Force Applying Downward to the ball