Asquirrel in a tree drops an acorn. how long does it take the acorn to fall 20 feet?

We use the equation of motion,

Here, S is the height, u is initial velocity and a is acceleration.

Given,

As  acorn falls from tree, therefore we take the value of and initial velocity .

Substituting these values in equation of motion,

Thus, the time taken by the acorn to fall 20  feet ( 6.096 m ) is 1.12 s.

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it