3. A ball has a volume of 6.86 x 103 m and average density of 8.40x105 g/m. (a) What is the mass of the ball and (b) what force in Newtons is required to hold it completely submerged under water? Density of water is 1000. kg/m Hint - first change grams to kg. Then find the ball's mass using Density = mass volume Draw a free body diagram of the ball which should have the ball's weight pointing down, the additional force pointing down, and the buoyancy force point up. Answers mass = 5.76 kg Force = 10.8 N 001 4. A small ferryboat is 4.00 m wide and 6.00 m long. When a loaded truck pulls onto it, the boat sinks an additional 4.00 cm into the river. What is the weight of the truck? Density of water is 1000. kg/m Answer 9410 N Hint - this is a buoyancy problem. You need to determine how much more volume of water is displaced when the truck is loaded then you can use the buoyant force equation. water Dinsety = 1000 kg/m 003.0 6.00 m 4.00m (1000kg) (6) (4) (4) x 5. I use a hydraulic lift filled with water. I press down with 200. N of force at point A. What weight can be supported at point B? Radius at A is 0.100 m and radius at B is 0.750 m Density of water is 1000. kg/m Answer 864 N B 0.600 m 200. N A