Help with 3 questions for general physics?

[sweetipie2216]

1.Three point charges are fixed in place in the right triangle diagrammed below, in which q1 = 0.81 µC and q2 = -0.53 µC. What is the electric force on the +1.0 µC charge due to the other two charges,degree measured counterclockwise from the +x-axis?

2. Two Styrofoam balls with the same mass m = 8.7 10-8 kg and the same positive charge Q are suspended from the same point by insulating threads of length L = 0.91 m (the figure below). The separation of the balls is d = 0.028 m. What is the charge Q?

3.Positive point charges are placed at three corners of a rectangle, as shown in the figure, in which d = 0.41 m. Take the +x-axis to point to the right.
(a) What is the electric field at the fourth corner?
degrees measured counterclockwise from the -x-axis

(b) A small object with a charge of +8.8 µC is placed at the fourth corner. What force acts on the object?
degrees measured counterclockwise from the -x-axis

here is a link to the diagrams. http://s685.photobucket.com/albums/vv220/sweetipie2216/

each picture is labeled with the question number.
I did work on these questions. I asked my teacher and T.A for help and they just added more to the confusion.

Here are my answers for number 3. I don't know if they are right or wrong. a)5.63e6N,205 degrees b)49.58N and 205 degrees.
If you can please give me a good explanation about how i can solve these with good detail and showing all the steps. You don't have to give me any answers.

 

[jbsteele]

For number 1, I have no clue where to start. For number 2, I tried using coulombs law with no success. For question 1, the electric force on the +1.0 µC charge due to the other two charges can be calculated using Coulomb's Law. Coulomb's Law states that the force between two point charges is given by F = kq1q2/r^2, where k is the Coulomb's constant, q1 and q2 are the charges, and r is the distance between them. In this case, the force on the +1.0 µC charge due to the two other charges is given by F = k(0.81 µC x (-0.53 µC))/d^2, where d is the distance between the charges. The direction of the force can be determined by considering the geometry of the triangle. The force will be in the direction of the hypotenuse (the line connecting the two other charges) and can be calculated using trigonometry. For question 2, the charge Q can be calculated using Coulomb's Law. The force between the two balls is given by F = kQ^2/L^2, where k is the Coulomb's constant, Q is the charge, and L is the length of the thread. Since the two balls are separated by a distance d, this can be substituted into the equation to give F = kQ^2/L^2-d^2. This equation can then be used to calculate the charge Q. For question 3, the electric field at the fourth corner can be calculated using Coulomb's Law. The electric field at a point due to a point charge is given by E = kq/r^2, where k is the Coulomb's constant, q is the charge, and r is the distance from the charge to the point. In this case, the electric field at the fourth corner is given by E = kq/d^2, where q is the charge at each corner and d is the distance from the fourth corner to each corner. The direction of the electric field can be determined by considering the geometry of the rectangle. The electric field will be in the direction of the diagonal of the rectangle, and can be calculated using trigonometry. To determine the force on the small

 

[tomcue]

First, let's address the first question. The electric force on the +1.0 µC charge is calculated using Coulomb's Law, which states that the force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. In this case, we have two charges (q1 and q2) acting on the +1.0 µC charge, so we need to calculate the force from each and then add them together.

To calculate the force from q1, we can use the formula F = k(q1)(q3)/r^2, where k is the Coulomb's constant (9x10^9 Nm^2/C^2), q3 is the charge of the +1.0 µC charge, and r is the distance between the two charges. In this case, r can be calculated using the Pythagorean theorem, since the distance between the two charges is the hypotenuse of the right triangle. So, r = √(d^2 + h^2) = √(0.028^2 + 0.41^2) = 0.411 m.

Plugging in the values, we get F1 = (9x10^9)(0.81x10^-6)(1.0x10^-6)/(0.411)^2 = 15.96 N.

To calculate the force from q2, we can use the same formula, but with q2 instead of q1. So, F2 = (9x10^9)(-0.53x10^-6)(1.0x10^-6)/(0.411)^2 = -10.47 N.

Since we are only concerned with the magnitude of the force, we can add these two values together and get the total electric force on the +1.0 µC charge, which is 15.96 N + (-10.47 N) = 5.49 N. To find the direction of the force, we can use trigonometry to find the angle of the force relative to the +x-axis. This can be done by taking the inverse tangent of the height of the triangle (0.028 m) divided by the base of the triangle (0.41 m), which gives us an angle of 4.9 degrees counterclockwise from the +x-axis.

Moving on to the