The force of buoyancy exerted by the atmosphere on a balloon is B in the upward direction and remains constant. The force of air resistance on the balloon acts opposite to the direction of velocity and is proportional to it. The balloon carries a mass M and is found to fall down near the earth's surface with a constant velocity v. How uch mass hsould be removed from teh balloon so that it may rise with a constant velocity v?

Explanation

Givwen , `a=2m/s^2`
`kl-(2g+2a) =0`

`rarr kl=2g+2a`
`=2xx9.8+2xx2`
= 19.6+4`
`rarr l= 23.6/100`
=0.236 ~~ 0.24 m`
When 1 kg body is added, tota mass `=(2+1) kg= 3kg`
Let elongation be `l_1`
`:. kl_1 = 3g+3a=3xx9.8+6`
`rarr l_1 = 33.4/100`
` 0.33.4~~0.36`
Further elongation = `l_1 - l`
` 0.36-0.24 = 0.12 m`.