Question

When a ship enters a sea from a river?
1. It rises a little
2. It rises or sinks depending on the material it is made of
3. It sinks a little
4. It remains at the same level

Answer 1

Correct Answer - Option 1 : It rises a little

The correct answer is It rises a little.

A ship rises a little when enters the sea from a river.

• Because of salinity, seawater has more density than river water.
• In the sea, the more buoyant force is exerted upon the ship than in the river. 
• With this more buoyant force and more density of seawater, the shipping volume inside the sea decreases so that the weight of the ship can be balanced.
• During the entry into the sea, the ship gains potential as well as kinetic energy.

• Buoyancy – the upthrust on an object is equal to the volume displaced by that object.
• Density – mass per unit volume (any kind of solid be it salt or impurities if present in water increases water density by negligibly changing the volume of the liquid)
• Waterline – point or line where the hull of the ship meets the water surface.