Q. A balloon has 5 g of air. A small hole is pierced into it. The air escapes at a uniform rate with a velocity of $4\ cms^{- 1}$. If the balloon shrinks completely in 2.5 s the average force acting on the balloon is
A) 2 dyne
B) 50 dyne
C) 8 dyne
D) 8 N
Explanation
(c) $F = v\frac{dm}{dt} = \frac{4 \times 5}{2.5}$ dyne $= 8$ dyne
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.