A ball is thrown verticaly upward with a velocity .u. from the ballon descending with velocity v. After what time, the ball with pass by the ballon?

A ball is thrown verticaly upward with a velocity .u. from the ballon

1.	A ball is thrown verticaly upward with a velocity .u. from the ballon descending with velocity v. After what time, the ball with pass by the ballon?
Answer» SOLUTION :`S_(f)=u_(R)t+1/2 a_(r) t^(2)` `O=(v+u)t-1/2gt^(2)` `t=(2(v+u))/(G)`