A wooden block of density 600kgm−3 and volume 5.0×10−3m3 is pushed below the surface of water and held stationary by means of a light string attached to the bottom of the tank.
Take ρw=1000kgm−3 and g=9.8ms−2.
(a) Draw a neat free-body diagram of the block showing all forces acting on it while it is held submerged.
(b) Calculate the tension in the string required to keep the block fully submerged and at rest.
(c) The string is now cut. What minimum mass must be tied to the block (assume it remains fully submerged) so that it does not shoot up to the surface? Neglect the mass of the string.