what happens toour weight when earth spin faster and what happens when it stop and why?
If the earth will stop spinning then you would weigh slightly less at the poles than at the equator due to centripetal force. You are also slightly closer to the center of the earth at the poles - also due to the earth's rotation (it causes the earth to bulge a bit). The net effect is a difference of about 0.05 m/s² between the equator and poles - meaning a sumo wrestler who weighs 200 kg at the south pole would weigh a mere 199 kg in Padang, Indonesia. Otherwise, your weight will increase if the Earth spin faster. These weight changes won't be applied at the poles.