WHEN A PERSON TRAVELLING ON MOON HIS/HER WEIGHT IS 30KG SO HOW WILL HE OR SHE WILL FEEL ND WHY?
30 kg is the person's mass, not the weight. A kilogram is not a weight dimension. Mass does not depend upon the local acceleration of gravity
An adult with a mass of 30 kg would be severely underweight amd malnourished.
There is such a thing as a kilogram of force(weight) but that it is not used by scientists. If a person had that weight on the moon, he or she would weigh 66 lb there and nearly 400 lb on Earth. That is much too much for an astronaut.