$(A)$ $d_Ad_F$ $(B)$ $d_B > d_F$ $(C)$ $d_A>d_F$ $(D)$ $d_A+d_B=2 d_F$
For equilibrium of $A$ :
$T+v d_A g=V D_f g$
$\therefore T=V_g\left(d_f-d_A\right) \cdots(1)$
$f \text { or } T > 0, d_f > d_A \text { or } d_A < d_f$
$(a)$ is the correct option
For equilibrium of $B$ :
$T+V d_f g=V d_B g$
$\therefore T=V_g\left(d_B \cdot d_f\right) \cdots$
$F \text { or } T > 0, d_B > d_f$
$(b)$ is the correct option
$\text { From (1) and (2) Vg }\left(d_f-d_A\right)=V g\left(d_B-d_f\right)$
$\therefore d_f-d_A=d_B-d_f$
$\therefore 2 d_f=d_A+d_B$
[Given: $\pi=22 / 7, g=10 ms ^{-2}$, density of water $=1 \times 10^3 kg m ^{-3}$, viscosity of water $=1 \times 10^{-3} Pa$-s.]
$(A)$ The work done in pushing the ball to the depth $d$ is $0.077 J$.
$(B)$ If we neglect the viscous force in water, then the speed $v=7 m / s$.
$(C)$ If we neglect the viscous force in water, then the height $H=1.4 m$.
$(D)$ The ratio of the magnitudes of the net force excluding the viscous force to the maximum viscous force in water is $500 / 9$.
