Question

A balloon of mass 1.5 kg (with contents) is descending with an acceleration equal to half the acceleration due to gravity. The mass of the contents that should be removed so that the balloon goes up with same acceleration is

• A. 0.25 kg
• B. 0.5 kg
• C. 0.2 kg
• D. 1 kg

Answer 1

The correct option is D 1 kg

1.5g - upthrust = (1.5) $\frac{g}{2}\Rightarrow$ upthrust $=1.5\frac{g}{2}$
Let X kg of mass be removed
$1.5\frac{g}{2}-(1.5-x)g=(1.5-x)\frac{g}{2}$
$\frac{1.5}{2}=(1.5-x)\frac{3}{2}\Rightarrow x=1kg$