A balloon with mass ′m′ is descending down with an acceleration ′a′ (where a<g). How much mass should be removed from it so that it starts moving up with an acceleration ′a′?
A
2mag+a
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
2mag−a
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
mag+a
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
mag−a
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is A2mag+a Let the upthrust of air be Fb, then for downward motion mg−Fb=ma...(1)
Let assume that mass m′ be removed from the balloon
So, when it start moving upward Fb−(m−m′)g=(m−m′)a...(2)
On adding equations (1)&(2) mg−(m−m′)g=ma+(m−m′)a m′=2mag+a