I would say that work is being done in all the situations because technically in physics work is done whenever force is applied through a distance.
Answer:
Explanation:
Distance of each of the charges from the center are equal . If this distance be d
d = .5 x length of diagonal of square
length of diagonal = 4√2
d = .5 x 4√2
= 2√2
potential at a point
V = k Q / r where k is a constant , Q is charge and r is distance of the point from the charge .
k = 9 x 10⁹
Total potential = 

= 
= 9 √2 x 10⁹ V .
The best plan to solve the problem of health problems among people, because of the contaminated surface water is to collect the runoffs in retention ponds for isolation and recovery of contaminants. Correct answer: D
This is tn eonly option from the given that is the most efficient and prodcutive way to solve this problem.
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Answer:
Using 3 periods to get an accurate reading:
3T = (6.40 S - 0.90 s) = 5.50 S So, T = 1.83 s
m = 0.250 kg
Using algebra:
k=
=
=2.95kg/sec