A solid sphere, disc and solid cylinder all of the same

A solid sphere, disc and solid cylinder all of the same mass and made of the same material are allowed to roll down (from rest) on the inclined plane, then

1. solid sphere reaches the bottom first
2. solid sphere reaches the bottom last
3. disc will reach the bottom first
4. all reach the bottom at the same time

For solid sphere,	K²	=	2
	R²		5

For disc and solid cylinder,	K²	=	1
	R²		2

As K²/R² for solid sphere is smallest, it takes minimum time to reach the bottom of the incline