A ball rises to the surface at a constant vel | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The ball is moving with constant velocity. Therefore,the net force acting on it is zero.Let the density of the ball be $\rho_b$ and the density of

Vedclass · Accepted Answer

$2$

Vedclass · Answer

(A) The ball is moving with constant velocity. Therefore,the net force acting on it is zero.Let the density of the ball be $\rho_b$ and the density of the liquid be $\rho_l = 3\rho_b$.The weight of the ball is $W = V \rho_b g$,where $V$ is the volume of the ball.As the ball is rising up,the buoyant force $F_B$ acts upwards and the viscous force (friction) $F_v$ acts downwards along with the weight $W$.The buoyant force is $F_B = V \rho_l g = V (3\rho_b) g = 3 V \rho_b g$.Since the velocity is constant,the net force is zero:$F_B = W + F_v$$F_v = F_B - W = 3 V \rho_b g - V \rho_b g = 2 V \rho_b g$.The ratio of the force of friction to the weight is:$\frac{F_v}{W} = \frac{2 V \rho_b g}{V \rho_b g} = \frac{2}{1}$.

$A$ ball rises to the surface at a constant velocity in a liquid whose density is $3$ times greater than that of the material of the ball. The ratio of the force of friction acting on the rising ball to its weight is (in $: 1$)

Similar Questions

$A$ $0.5 \,kg$ block of brass (density $=8 \times 10^3 \,kg \,m^{-3}$) is suspended from a string. What is the tension in the string if the block is completely immersed in water? $(g=10 \,ms^{-2})$

$A$ cubical block is floating in a liquid with one-fourth of its volume immersed in the liquid. If the whole system accelerates upward with an acceleration of $g / 4$,what will be the fraction of the volume immersed in the liquid?

What is buoyant force?

$A$ rectangular block of size $10 \,cm \times 10 \,cm \times 15 \,cm$ is floating in water with the $10 \,cm$ side vertical. If it floats with the $15 \,cm$ side vertical,then the level of water will ..........

$A$ body of density $\rho$ is dropped from rest at a height $h$ into a lake of density $\sigma$ $(\sigma > \rho)$. The maximum depth to which the body sinks before returning to float on the surface is (neglect air dissipative forces).

Vedclass Test Series

Exam Paper Generator

Online Exam Module