JEE Main 2022 Physics question
A balloon has mass of 10 g in air. The air escapes from the balloon at a uniform rate with velocity 4.5 cm/s. If the balloon shrinks in 5 s completely. Then, the average force acting on that balloon will be (in dyne).
Answer: (B)
Solution
The mass of air escaping per second is 10/5 = 2 g/s, so = (dm/dt) = dyne.