(a). Height h = 2.5 m
Mass of the sphere M = M
from law of conservation of energy , potential energy at height h = kinetic energy at the bottom
M g h = ( 1/ 2) M v ^ 2 * [ 1 + ( k / r ) ^2 ] Since its both rolling and trnaslating
2gh = v ^ 2 * [ 1 + ( 2/ 3) ]
= v ^ 2 * ( 5/ 3 )
v ^ 2 = √[ 6gh / 5 ]
v = 5.422 m / s
(b). Height h = 2.5 m
from law of conservation of energy , potential energy at height h = kinetic energy at the bottom