21. A particle rests on the top of hemisphere of radius 'r'. It begins to slide without friction
down the smooth surface of hemisphere and
leave the surface of hemisphere at height 'h'
above ground making angle with vertical.
The value of O is

Two rigid transformations are used to map δhjk to δlmn. the first is a translation of vertex h to vertex l. what is the second transformation? a reflection across the line containing hk a rotation about point h a reflection across the line containing hj a rotation about point k