Question

Why is it easier to swim in sea water than in river water?

Answer 1

1. Sea water contains dissolved salts which make its density more than river water.
2. And we know that upward buoyant force is directly proportional to the density of the liquid in which the object is submerged.
3. Hence upthrust is more in seawater than river water.
4. So it is easier to swim in seawater than in river water.
5. The denser the fluid, the more the upthrust; this is why swimming in seawater is easier than in river water.