# 1. THE BIRD IS SITTING ON THE FLOOR OF A WIRE CAGE . SUDDENLY IT STARTS FLYING INSIDE THE CAGE. WILL THE GIRL HANDLING IT EXPERIENCE MORE WEIGHT OR LESS WEIGHT? 2. A BIRD IS SITTING ON THE FLOOR OF A GLASS CAGE. SUDDENLY IT STARTS FLYING INSIDE THE CAGE. WILL THE BOY HANDLING IT EXPERIENCE MORE WEIGHT OR LESS WEIGHT? SIR PLZ TELL THE LOGIC & DIFFERENCE B/W WIRE & GLASS CAGE? WHICH OF THE ABOVE CASES IS SIMILAR TO MOVING LIFT CASE & HOW? THANK U

69 Points
12 years ago
Dear saumya shivhare,

1) Girl experiences less weight  when bird statrts flying in the cage. in the cage the bird exerts the force on the rods as well as on the base of the cage. the total force is not equal its wieght because force disperse between rods of cage.so girl experiences less weight

2) in the boy case the force dispersion is not occuring. the glass cage experiences the total force which is equal to its weight.

so u can say that boy experiences same weight after bird is start flying

All the best.

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Rathod Shankar Singh

IIT Bombay
deeksha sharma
40 Points
12 years ago

Dear Saumya

In case of wire cage, the outer atmosphere will interfere. Thus the girl handling the cage will experience the force as the bird flies, because the cage becomes lighter. (Internal forces can change the weight as the system is not isolated)

While in case of glass cage, there isno interference of atmosfhere. Any movements inside the cage will not change the overall weight of the cage. Thus no force will act on the hands of the girl handling the cage.

(This is because in an isolated system, internal forces cannot change the overall weight of the body.)

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Rishi Sharma
2 years ago
Dear Student,