Question

What if earth suddenly stop rotation?

Answer 1

Every free body (not fixed to the ground) will become a nearly horizontal projectile (due to their velocity at a tangent to Earth during its rotation)

Explanation:

Anything with motion will maintain its motion (Newton's 1st Law), so all of us will become immediate projectiles at high speeds (depending on your location's latitude). At the poles you'll be fine (zero m/s). At the equator you'll be going about 460m/s, so that will be problematic. Basically take a look around you, the nearest fixed eastward item... a tree, a building, you'll be colliding with that soon.