Student mixes 5 g of sand into a beaker of 20 g of water. is this a physical or chemical change-why?

Physical because it doesn't do with fire

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts

The velocity would be 2