Question

A circular cylinder partly filled with a liquid is rotated about its axis at w rad/s without spilling. At the walls, the rise of liquid surface above the original level will be -

• A. w² r²/8g
• B. w² r²/g
• C. w² r²/4g
• D. w² r²/2g

Answer 1

Answer:

C. w² r²/4g

When a circular cylinder partially filled with a liquid is rotated about its axis at w rad/s, the centrifugal force causes the liquid to rise along the walls of the cylinder. The height of the liquid rise can be determined by balancing the centrifugal force and gravitational force acting on a liquid element. By doing this, we find that the rise of the liquid surface at the walls is given by w² r²/4g