Question

The pans of a physical balance are in equilibrium. Air is blown under the right hand pan, then the right hand pan will:

• A. move up
• B. move down
• C. move erratically
• D. remains at the same level

Answer 1

The correct option is B move down

The air medium can be considered a very sparse fluid medium. When air is blown under the right hand pan, the upthrust from air fluid is destroyed, thus the upthrust on left hand pan becomes the unbalanced force and causes the right hand pan to move down.