The Bat Life: Batman is undercover, and to prevent anyone from recognizing his voice (or Bruce Wayne's) he inhales a very dilute Helium gas (search YouTube for "voice after helium” to see the effects). The helium is stored ina cylindrical chamber as shown.
During a fight one of the steel balls gets dislodged. What will happen to the piston?
The Bat Life: Batman is undercover, and to prevent anyone from recognizing his voice (or Bruce Wayne's) he inhales a very dilute Helium gas (search YouTube for "voice after helium” to see the effects). The helium is stored ina cylindrical chamber as shown.
During a fight one of the steel balls gets dislodged. What will happen to the piston?
The correct option is B It will move up
Initial free body diagram -
.
When the system was in equilibrium, the force applied by the steel balls on the piston was offset by the force applied by the gas on the piston.
Just after removing the ball -
.
The instant the ball is dislodged the downward force acting on the piston reduces from 19.6 N (i.e., 2×9.8 N) to 14.7 N (1.5× 9.8 N). However the pressure of the helium gas has not changed. Hence there is an unbalanced force in the upward direction. This upward force will push the piston up. After some time, the weight of the balls would equal the force exerted by the helium gas and the system would eventually come to rest.
It will move up
Initial free body diagram -
.
When the system was in equilibrium, the force applied by the steel balls on the piston was offset by the force applied by the gas on the piston.
Just after removing the ball -
.
The instant the ball is dislodged the downward force acting on the piston reduces from 19.6 N (i.e., 2×9.8 N) to 14.7 N (1.5× 9.8 N). However the pressure of the helium gas has not changed. Hence there is an unbalanced force in the upward direction. This upward force will push the piston up. After some time, the weight of the balls would equal the force exerted by the helium gas and the system would eventually come to rest.
