Explain why A fluid flowing out of a small hole in a vessel results in a backward thrust on the vessel

Explain why objects moving in fluids must have special shapes.

Explain why objects moving in fluids must have special shapes.

Explain why a small piece of stone is not attracted towards another big piece of stone on the earth's surface ?

A hollow sphere is filled with water through a small hole in it. It is hung by long thread and as water slowly flows out from the hole at the bottom, one finds that the periods of oscillation first increases and then decreases. Explain. Why.

A small amount of silica gel and a small amount of anhydrous calcium chloride are placed separately in two corners of a vessel containing water vapour. What phenomena will occur ?