Answer:
2271.16N/C upward
Explanation:
The diagram well illustrate all the forces acting on the mass. The weight is acting downward and the force is acting upward in other to balance the weight.since the question says it is motionless, then indeed the forces are balanced.
First we determine the downward weight using

Hence for a mass of 3.82g 0r 0.00382kg we have the weight to be


To calculate the electric field,

Since the charge on the mass is negative, in order to generate upward force, there must be a like charge below it that is repelling it, Hebce we can conclude that the electric field lines are upward.
Hence the magnitude of the electric force is 2271.16N/C and the direction is upward
Answer:
The current is 
Explanation:
From the question we are told that
The length of the segment is
The current is
The force felt is
The distance of the second wire is 
Generally the current on the second wire is mathematically represented as

Here
is the permeability of free space with value
=> 
=> 
"1 watt" means 1 joule of energy per second.
75 W means 75 joules/sec .
Energy = (75 Joule/sec) x (12 min) x (60 sec/min)
Energy = (75 x 12 x 60) (Joule-<em>min-sec</em> / <em>sec-min</em>)
<em>Energy = 54,000 Joules</em>
Answer:
30 hours
15 hours.
Explanation:
Let the Kelly used sprinkler for t hours and Gracia used the sprinkler for the rest ie (45 - t) hours .
Water output by Kelly = (35 x t) L
Water output by Gracia = 20 ( 45 - t ) L
Total output = 35t + 20(45 - t)
So, 35 t + 20 (45 - t ) = 1350
35 t + 900 - 20 t = 1350
15 t = 450
t = 30 hours
So Kelly used sprinkler for 30 hours and Gracia used it for 45 - 30 = 15 hours.
Length of the sheet is given as

width of the sheet is given as

now let say its thickness is "t"
so the volume of the sheet is given as



mass of the sheet is given as

now we have


by solving above we have

so the thickness of sheet will be above