The force that opposes the movement of an object through
water is called drag. This is a type of frictional force. This force normally
depends on the density and the viscosity of the fluid in question. The liquid
which has more density and more viscosity or stickiness will produce a greater
amount of drag force on an object than a fluid that is less dense and less
viscous in nature. River water normally
has less drag than that of sea water.