A rectangular concrete ballast block is used in underwater tests.
Explain why the forces on the block at the bottom of the tank cause the block to be stationary.
When the block is at the bottom of a shallow tank, the top surface of the block is 3.00 m3.00\text{ m}3.00 m below the surface of the liquid. The force acting on the top surface of the block due to the weight of the liquid is 2940 N2940\text{ N}2940 N. The gravitational field strength is g=9.8 N/kgg = 9.8\text{ N/kg}g=9.8 N/kg. Calculate the density of the liquid in this tank.
The block is then lowered into a very deep test tank filled with a different liquid. When the block is at a depth of 3.00 m3.00\text{ m}3.00 m in this deep tank, the force due to the pressure of the liquid on its top surface is 3060 N3060\text{ N}3060 N.
Determine the force due to the weight of the liquid on the top surface of the block when it is at the bottom of this deep tank at a depth of 35.5 m35.5\text{ m}35.5 m. Give your answer to 3 significant figures.