A disc is at rest at the top of a rough incined plane. It rolls without slipping. At the bottom of inclined palne there is a vertical groove of radius .R.. In order to loop the groove, the minimum height of incline required is:

A disc is at rest at the top of a rough incined plane. It rolls withou

1.	A disc is at rest at the top of a rough incined plane. It rolls without slipping. At the bottom of inclined palne there is a vertical groove of radius .R.. In order to loop the groove, the minimum height of incline required is:
Answer» `(15R)/4` `(9R)/4` `(5R)/2` `(7R)/5` Answer :A