Answer:
Heya how have you been doing
Hmm, I will come back to this one just to help. :)
Answer:
Explanation:
Force between two charges is given by the following expression
F =
Q₁ and Q₂ are two charges and d is distance between two.
.1 = 
If Q₁ becomes three times , force will become 3 times . Hence force becomes .3 N in the first case.
Force F = .3 N
If charge becomes one fourth , force also becomes one fourth .
F= 
= .025 N.
Answer:
The vector sum of all forces acting on it is zero, its at equilibrium.
Explanation:
The bag of marbles hanging on a spring scale applies its weight downwards, which was counterbalanced by the reaction from the spring scale (obeying the Newton's third law of motion). And since no external forces are applied to the system, thus the equilibrium of the system.
If the weight of the bag is greater than the reaction from the spring scale, the scale breaks and the system would not be balanced.