For the folloing 6 questions, I got completely different (way off) answers from the ones given in the textbook. This is really driving my crazy. I checked my work many times but can't find out what I did wrong. If anyone is interested in physics problems and have the time, I hope you can help me check out whether the answers in the textbook are correct or not, so that I can know if I am correct. I really appreciate for your help!
I am wondering if I am calculating something seriously wrong so that I am getting way off answers for all these questions. I am afraid and frustrated now that I am losing confidence in this topic.
1) A point charge of +3.8x10^-6 C is placed 0.20 m to the right of a charge of -2.0x10^-6 C. What is the force on a third charge of +2.3x10^-6 C if it is placed
1a) 0.10 m to the right of the second charge?
[assuming the second charge is the charge on the right side(+3.8x10^-6C), I got an answer of 7.4N[right], but the answer is 7.9N[left] ]
1b) where would the third charge experience a net force of zero?
[I got an answer of 0.53 m to the left of the -2.0x10^-6C charge, but the answer given is 1.2x10^-2 m [right of smaller charge] ]
2) 4 objects, each with a positive charge of 1.0x10^-6 C, are placed at the coreners of a 45-degree rhombus with sides of length 1.0m. Calculate the magnitude of the net force on each charge.
[I got 2.2x10^-2 N and 1.9x10^-2 N respectively, but the answers provided are 8.4x10^-3 N and 1.9x10^-2 N respectively.]
3) 3 charges of +1.0x10^-4 C form an equilateral triangle with side length 40cm. What is the magnitude and direction of the electric force on each charge?
[I got an answer of 9.7x10^2N[90 degrees from the line joining the other charges], but the answer provided is 8.9x10^2 N[90 degrees away from the line connecting other charges] ]
