# Coulomb's Law/Electric field questions

I am not sure how to approach any of these.

1- A 4.7-µC point charge is located at x = 0.9 m, y = 3.1 m, and a -3.9-µC point charge is located at x = 2.1 m, y = -1.9 m.
(a) Find the magnitude and direction of the electric field at x = -2.7 m, y = 0.9 m. magnitude:
direction: °

(b) Find the magnitude and direction of the force on a proton at x = -2.7 m, y = 0.9 m. magnitude:
direction: °

2- An electron is released from rest in a weak electric field given by = -3.00 10-10 N/C . After the electron has traveled a vertical distance of 1.9 µm, what is its speed? (Do not neglect the gravitational force on the electron.)

3- A fixed point charge of +2q is connected by strings to point charges of +q and +4q. Find the tensions T1 and T2. (Use q, d and k as necessary.)
T1 =
T2 =

Related Introductory Physics Homework Help News on Phys.org
tiny-tim
Homework Helper
Hi krtica! Show us what you've tried, and where you're stuck, and then we'll know how to help!

Start with 1(a). Hi krtica! Show us what you've tried, and where you're stuck, and then we'll know how to help!

Start with 1(a). In regards to question 1, I plotted each point on a x-y coordinate system. The three points form a right triangle. The opposite and adjacent lengths I took for each separate electric field. To find the magnitude of both, I used the Pythagoreum Theorem.

Concerning the other questions, I am not really even sure where to begin.

tiny-tim
ok, well, if it didn't give the right result, show us your calculations, and then we'll know how to help! 