NTA Abhyas JEE Main2020PhysicsMechanical Properties of FluidsPractice
A hollow cylinder of mass m made heavy at its bottom is floating vertically in water. It is tilted from its vertical position through an angle θ and is left. The restoring force acting on it is
Options
- Am g cos θ
- Bm g sin θ
- Cm g 1 cos θ - 1
- Dm g 1 cos θ + 1
Correct answer
C. m g 1 cos θ - 1
Step-by-step solution
Let l be the length of the cylinder in water it is in the vertical position and A be the cross-sectional area of the cylinder. As cylinder is floating so Weight of cylinder = upward thrust m g = A l ρ g or m = A l ρ When the cylinder is tilled through an angle θ , length of cylinder in water = l cos θ Weight of water displaced = l cos θ A ρ g Restoring force = l A ρ g cos θ = l A ρ g = l A ρ g 1 cos θ - 1 = m g 1 cos θ - 1