Question

a glass Of water has an ice the just touches the rim will it overflow give reaaon

Answer 1

No. Water will not overflow when ice cube floating in a glass of water melts.

Density = Mass/Volume

Density of ice is slightly less than that of water.

Hence ice cube has more volume than equal mass of  water.

When ice cube melts, water from the molten cube will occupy the space in the glass which was originally occupied by the ice cube.