Point charges arranged as a trianngle

[jenzao]

Homework Statement

Consider three charges at the vertices of an equilateral triangle of side a = 7 cm. qA = +2 µC, qB = +2 µC, and qC = -1 µC. (see attached picture)

Find the x- and y- components of the electric force acting on qC

Homework Equations

i am doing everything right, but getting wrong answer ?

The Attempt at a Solution

x-comp cancel obviously, so I am left with finding y-comp...

F = kqAqC/r^2
= 2.571e-1

sin60(2.571e-1) = 2.2266e-1
multiply by 2 = 4.453e-1 N (this is wrong though)

i can't see the prob. The forces both point in positive y direction, so the y vectors sum
please help, thanks!

 

[rootX]

The Attempt at a Solution

x-comp cancel obviously, so I am left with finding y-comp...

F = kqAqC/r^2
= 2.571e-1

sin60(2.571e-1) = 2.2266e-1
multiply by 2 = 4.453e-1 N (this is wrong though)

=k.qA.qC/r^2
=9E9 x 2E-6 x 1E-6/0.07^2
=3.67

I see you are dividing by 7
Two mistakes it's 7cm and then its r^2

 

[nlightner]

I would first commend the student on their attempt to solve the problem and their use of the correct equations. However, it is important to double-check calculations and make sure all units are consistent.

In this case, it seems like there may be a mistake in the calculation of the electric force. It is important to remember that the electric force is a vector quantity and has both magnitude and direction. The direction of the force acting on qC will depend on the relative positions of the charges and the direction of the electric field they create.

I would suggest reviewing the calculation and making sure the direction of the force is taken into account. It may also be helpful to draw a vector diagram to visualize the forces acting on qC. Additionally, checking the units and making sure they are consistent can help identify any errors.

If the issue persists, it may be helpful to seek assistance from a classmate or the instructor for further clarification. As a scientist, it is important to approach problems with a critical mindset, double-checking calculations and seeking clarification when needed.