Case:A lets assume volume of cube is
V.
Forces in Y-direction:
Fy=(σVg)−(ρVg)=σVax
ay=(σ−ρ)gσ
Forces in x- direction: Pseudo force will be applied i −ve x−direction as system is moving with acceleration, g/2.
Pseudo force =−(ρVg/2)
Fx=σVax=(σVg)−(ρVg/2)⇒ax=(−ρ+2σ)g2σ
Now, axay=(2σ−ρ)2(σ−ρ)
Case:B
Fy=σVay=(ρVg)−(σVg)
ay=(ρ−σ)gσ
ax=g
axay=σ(ρ−σ)
Case:C
Fy=σVay=(ρVg)−(σVg)
ay=(ρ−σ)gσ
As system is rotating with ω=√2g3x. Hence Pseudo force on tube is Fpseudo=ρVω2(3x/2)
Fx=Fpseudo=σVax=ρVω2(3x/2)
⇒ax=ρσ.g
Now, axg=ρσ
Case:D
When there is air then, Tsinθ=M.a Tcosθ=Mg
⇒tanθ=a/g
When there is liquid of density, ρ<σ, then
Pseudo force =(ρVa)−(σVa)
Tsinθ=(ρVa)−(σVa) Tcosθ=(ρVg)−(σVg)
From above, we have, tanθ′=a/g
Hence tanθtanθ′=1:1