A nail is located below the point of suspensions of a simple pendlum of length .l.. The bob is released from horizontal position. If the bob loops a verticle circle with nail as centre, find the distance of nail from point of suspension.

A nail is located below the point of suspensions of a simple pendlum o

1.	A nail is located below the point of suspensions of a simple pendlum of length .l.. The bob is released from horizontal position. If the bob loops a verticle circle with nail as centre, find the distance of nail from point of suspension.
Answer» SOLUTION :Form the principal of conservation of MECHANICAL energy PE at the HORIZONTAL position = KE at the lowest position. `mgl = (1)/(2) mv^(2)` To loop the verticle circle, `v^(2) = 5gh (1-x)` where .x. is the distance of nail from point of suspension, and .v. is the velocity at lowest point of path `(mgl=(1)/(2)m.5g(l-x)),l=(5)/(2)(l-x), "" x = 3l//5`