Q. An air-tight cage with a parrot sitting in it is suspended from the spring balance. The parrot starts flying. The reading of the spring balance will
A) Increase
B) Decrease
C) Not change
D) Be zero
Explanation
(c) The system is closed. The weight of parrot is suppresses the base of air cage with a weight equal to weight of parrot. These are internal forces. So there will be no change in the reading of the spring balance
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.