Question

Why does a block of plastic released under water come up to the surface of water?​

Answer 1

Answer:

Density of plastic block is less than the density of water. ... When it is put completely in water, buoyant force on it becomes more than its weight. Thus, when it is released, it comes up to the surface of the water due to a net upward force acting on it.

Answer 2

Answer:

The buoyant force acting on the block of plastic is more than its weight. As a result of this, it comes up when released under water. The cause of this larger buoyant force on the block of plastic is due to its density being smaller than that of water.