Answer:
Approximately 0.979 J.
Explanation:
Assume that the two charges are in vacuum. Apply the coulomb's law to find their initial and final electrical potential energy 
.
,
where
- The coulomb's constant
, 
and 
are the sizes of the two charges, and
is the separation of (the center of) the two charges.
Note that there's no negative sign before the fraction.
Make sure that all values are in SI units:
;
;
- Initial separation:
; - Final separation:
.
Apply Coulomb's law:
Initial potential energy:
.
Final potential energy:
.
The final potential energy is less negative than the initial one. In other words, the two particles gain energy in this process. The energy difference (final minus initial) will be equal to the work required to move them at a constant speed.
.
The second one, air is a poor conductor. If it weren't it wouldn't be used as such in construction. It's not the best insulator, but is quite efficient, and much cheaper to include a layer of air inside a wall than to add additional layers of asbestos :)
Sound travels at approximately 1,100 feet per second (766 miles per hour). Radio waves travel at the speed of light, which is approximately 186,000 miles per second. This means that in the time radio waves travel the length of a football field, light can travel further than all the way around the world.
I would assume air resistance is negligible and so the acceleration of the package would be approximately 9.81 m/s².
Taking downwards as positive, use v²=u²+2as.
v²=(-2)²+2(9.81)(14)
v=16.7 m/s
