Question

A bunch of balloons with a sandbag of mass $m$ attached with a string is rising with an acceleration $a$. A fraction of sand is dropped from it, the acceleration of balloon will ___ .

• A. decrease
• B. increase
• C. remain the same
• D. none of these

Answer 1

The correct option is B

increase

The upthrust/buoyancy on the balloons-bag system depends on the number of balloons.

Since the number of balloons remains the same, upthrust does not change. But, the mass of the system is reduced as some sand is dropped from the bag.

For the same amount of force, a reduction in mass of the body results in increased acceleration.