Three charged particles are located at the corners of an equilateral triangle as shown in the figure below (let q = 2.20 µC, and L = 0.810 m). Calculate the total electric force on the 7.00-µC charge.   What is the magnitude , what is the direction?

(a) Calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 9.0 g. Silver has 47 electrons per atom, and its molar mass is 107.87 g/mol.   (b) Imagine adding electrons to the pin until the negative charge has the very large value 2.00 mC. How many electrons are added for every 109 electrons already present?

(a) Calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 13.0 g. Silver has 47 electrons per atom, and its molar mass is 107.87 g/mol.

8 Two moving charged particles exert forces on each other because each creates a magnetic field that acts on the other. These two "Lorentz" forces are proportional to vix (2 xr) and 2 x (vi x-r), where is the vector between the particle positions. Show that these two forces are equal and opposite in accordance with Newton's third law if and only if rx (vi × 2) = 0.

6 The force = +3 + 2k acts at the point (1, 1, 1). Find the torque of the force about (a) (b) the point (2, -1, 5). Careful about the direction of ŕ between the two points. the line = 21-+5k+ (i-+2k)t. Note that the line goes through the point (2, -1, 5).

5 Find the total work done by forces A and B if the object undergoes the displacement C. Hint: Can you add the two forces first?

1 F2 F₁ -F₁ F6 F₂ S A Work done on the particle as it moves through the displacement is positive. True False by the force F

A student measuring the wavelength produced by a vapour lamp directed the lightthrough two slits with a separation of 0.20 mm. An interference pattern was created on the screen,3.00 m away. The student found that the distance between the first and the eighth consecutive darklines was 8.0 cm. Draw a quick picture of the setup. What was the wavelength of the light emittedby the vapour lamp?

A ball is tied to one end of a string. The other end of the string is fixed. The ball is set in motion around a vertical circle without friction. At the top of the circle, the ball has a speed of ; = √√ Rg, as shown in the figure. At what angle should the string be cut so that the ball will travel through the center of the circle? The path after string is cut R