Question
A weightless rubber balloon has 100 gm of liquid of density 2 gm/cc and is suspended by a string. What will be the tension in the string when balloon is fully immersed in water?
Solution
Mass of liquid = 100 gm
Density of liquid = 2 gm/cc
Volume of ballon containing liquid = 50cc
When it is fully immeresed in water, it will displace 50cc of water.
Therefore upward thrust on ballon is given by,
U = 50 x 1
= 50 gmf
Tension in string is,
T=100 - 50
= 50 gmf
