Question

Ravi slowly pushes an empty, closed plastic bottle down into a bucket of water. He feels a greater upward push as more of the bottle goes under water. This is because:

The same metal block is fully dipped first in tap water and then in very salty water. The buoyant force on it is:

Two blocks A and B are held fully under water and then released. The figure shows the weight and the buoyant force on each block (arrows to scale). (a) Find the net force on each block just after release, with direction. (b) Which block will rise and float, and which will sink? Give reason.

A spring balance reads 12 N when a stone hangs from it in air. When the stone is fully dipped in water (still hanging), the reading falls to 7.5 N. (a) Find the buoyant force on the stone in newton. (b) Would the reading be more or less than 7.5 N if the stone were dipped in salty water? Enter the answer to (a).