What if the gravitational constant (G) became exactly 0 for 1 second?

Imagine gravity completely disappears everywhere for exactly 1 second, then instantly comes back.

What happens to us? Do people and cars lift off the ground? Do buildings collapse when gravity returns? Does the atmosphere start drifting away? Would cities survive? All other forces stay the same, only gravity vanishes briefly.

Is 1 second enough to devastate humanity? if not how much would be needed?