Where is the point of zero gravity on earth

Could someone me find the answer to this problem.

Atoms seldom exist as independent particles in nature a) as single particles, most atoms have low potential energy b) their electronegativity is much lower when they combine with other atoms c) atoms are more stable when they combine with other atoms d) neutral particles are rare

As you lift an 88 n box straight upward you produce a power of 72 w. what is the speed of the box?