Physics - Fluid Question with Solution | TestHub

Let $V$ be the volume of the ball and $\rho$ be the density of the material of the ball.

Weight of the ball, $W=V\rho g$

Density of the liquid is given as $3\rho$.

Buoyant force acting on the ball in the upward direction, $F_B=V(3\rho )g=3V\rho g=3W$

Since the ball rises at a constant velocity, its acceleration is zero, meaning the net force acting on it is zero. The forces acting on the ball are the upward buoyant force, the downward weight, and the downward force of friction (viscous drag).

$F_B=W+F_v$

$3W=W+F_v$

$F_v=2W$

The ratio of the force of friction to its weight is:

$\frac{F_v}{W}=\frac{2W}{W}=\frac{2}{1}$

The ratio is $2:1$.

Answer: $2:1$