Answer:
C. The mattress decreases the man's force.
Explanation:
Has to be c
Explanation :
It is given that, q and 4q are placed at a distance of l.
Let x is the distance where third charge is placed so that the entire three charge system is in static equilibrium.
Equilibrium means the net force acting on the system of charges is equal to zero. Let Q is the third charge.
So, ![\dfrac{kqQ}{x^2}=\dfrac{k(Q)(4q)}{(l-x)^2}](https://tex.z-dn.net/?f=%5Cdfrac%7BkqQ%7D%7Bx%5E2%7D%3D%5Cdfrac%7Bk%28Q%29%284q%29%7D%7B%28l-x%29%5E2%7D)
On solving,
![x=\dfrac{l}{3}](https://tex.z-dn.net/?f=x%3D%5Cdfrac%7Bl%7D%7B3%7D)
For magnitude :
![\dfrac{kqQ}{(l/3)^2}=\dfrac{kq4q}{l^2}](https://tex.z-dn.net/?f=%5Cdfrac%7BkqQ%7D%7B%28l%2F3%29%5E2%7D%3D%5Cdfrac%7Bkq4q%7D%7Bl%5E2%7D)
using ![x=\dfrac{l}{3}](https://tex.z-dn.net/?f=x%3D%5Cdfrac%7Bl%7D%7B3%7D)
![Q=\dfrac{4q}{9}](https://tex.z-dn.net/?f=Q%3D%5Cdfrac%7B4q%7D%7B9%7D)
So, a charge of -4q/9 is at a distance of l/3 is placed. It is placed to the right of +q.
Liquid water is not itself wet, but can make other solid materials wet. Wetness is the ability of a liquid to adhere to the surface of a solid, so when we say that something is wet, we mean that the liquid is sticking to the surface of a material.
If the resistance is ohmic (follows Ohm's law of V=IR), then current should be
I = V/R, where I is current, V is voltage, and R is resistance.
Current in this case will be
I = (120V)/(100Ω)
I = 1.2A