With what minimum speed `v` must a small ball should be pushed inside a smooth vertical tube from a heoght `h` so that it may reach the top of the tube? Radius of the tube is `R` .

Answer

B

Explanation

`v_(t op)=sqrt(v^(2)-2g(2R-h))`
To just complete the verticle circle `v_(t op)` may be zero.
`:. 0=sqrt(v^(2)-2g(2R-h))`
or `v=sqrt(2g(2R-h))`