Answer:
this is a difficult question but I will try to answer it answer for this is 3220 a + b b u s y d l new
The pressure exerted by the block on the table is given by:

where W is the weight of the box, and A is the bottom surface area of the box.
The weight of the box is: 
Substituting into the first equation, we find the pressure:

Current = charge/time = (2 c)/(0.00024 sec)= 8,333 Amps !
Answer:
Explanation:
The negative only matters reallly if you are dealing with a 2d system. I could even define down as positive and up as negative. However, usually you are taught that down is negative. It really doesn't matter because a force is a force. It is only given a direction relative to another force or vector direction.