Question regarding a charge problem

[ucdawg12]

Three charges are fixed to an xy coordinate system. A charge of +18 microC is on the y-axis at y = +3.0m. A charge of -12 microC is at the origin. Lastly a charge of +45 mircoC is on the x-axis at x = +3.0m. Determine the magnitude and direction of the net electrostatic force on the charge at x = +3m. Specify the direction relative to the -x axis.

With this problem ^ I am not really sure I understand how to set it up, if they want the force on the x axis, why do they give me the y coordinate and the charge? I tried setting it up with the f= (kq1q2)/r^2 but once I found the two forces using the origin charge as the q2 I wasnt really sure how to move forward.


thanks

 

[dextercioby]

How about writing the 2 vectors with their 2 components clearly stated and them add them "on components".I'm sure it won't fail.

Daniel.

 

[wais]

for the question! Let's break down the problem step by step to help you understand how to set it up and solve it.

First, let's draw a diagram of the situation described. We have three charges fixed in an xy coordinate system, with +18 microC on the y-axis at y=+3.0m, -12 microC at the origin, and +45 microC on the x-axis at x=+3.0m. The charge at x=+3.0m is the one we are interested in finding the net electrostatic force on.

Next, let's identify the relevant variables and equations we can use to solve this problem. We have the charges (+18 microC, -12 microC, and +45 microC) and their respective positions in the coordinate system. We also have the equation for electrostatic force, F = (k*q1*q2)/r^2, where k is the Coulomb's constant, q1 and q2 are the two charges, and r is the distance between them.

Now, let's set up the equation for the net electrostatic force on the charge at x=+3.0m. We will need to calculate the force between this charge and the other two charges, and then add them together to find the net force. Remember that forces are vectors, so we need to consider both magnitude and direction.

First, let's find the force between the charge at x=+3.0m and the charge at the origin. We can use the equation F = (k*q1*q2)/r^2, where q1 is the charge at x=+3.0m (+45 microC) and q2 is the charge at the origin (-12 microC). The distance between them is the x-coordinate, which is 3.0m. Plugging in the values, we get F = (9*10^9)*((45*10^-6)*(-12*10^-6))/(3^2) = -0.81 N.

Next, let's find the force between the charge at x=+3.0m and the charge at y=+3.0m. Again, using the same equation, we get F = (9*10^9)*((45*10^-6)*(18*10^-6))/(3^2) = 0.405 N. Note that this force is in the +x