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:

An iron nail sinks in water, but a ship made of tonnes of iron floats. Explain.

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).