Two metal bearings both have a positive charge of unequal and unknown magnitude. They are brought into contact and then separated. After separation, the charge on one bearing is measured to be 3.50 C.

It turns out that there is an electric field that points inward towards the center of the earth that has a magnitude of 100 N/C near the Earth's surface. Estimate the total charge of the earth needed to support such a field. Where do you think all this charge comes from?

3- Consider a sphere with a radius of 0.1 m and a total charge of 1 mC distributed uniformly over the entire sphere. The center of the sphere is at the origin. I now hollow out a cavity of radius 0.04 m centered at x = 0.05m. What is the force on a 0.1 mC load located at x = 0.15m? At x = -0.15 m? What would be the force on this load if it were located at the center of the cavity?

1. Find to three significant digits, the charge and the mass of the following particles: (a) a singly ionized sodium atom, Na+ (b) a chloride ion Cl- (c) an ionized hydrogen atom, represented as H+ (d) the center of an ammonia molecule, modeled as an N³- (e) the molecular ion H20- Hint: You can look up the mass of a neutral atom on a periodic table of elements.

3) a)What are the magnitude and direction of the force exerted on a 4.41 pC charge by a 184 N/C electric field that points due east? magnitude direction ---Select- v b) You charge a piece of aluminum foil (mass =7.46 g) by touching it to a charged rod. The charged rod gives the aluminum foil a charge of 13 µC. Your professor brings a charged plate over and tells you to put the aluminum foil on top of the plate. To your surprise the aluminum foil hovers motionless in the air above it! Calculate the value of the electric field from the charged plate (assume it is a uniform field and the aluminum foil is a point charge). magnitude N/C direction -Select-- v

There is a charge A of -2.3 uC at x = 1 cm and y = 4 cm. There is a charge B of -6.6 uC at x = 7 cm and y = -2 cm.  a) what is the magnitude of the force (in Newton's) of A on B? b) is the direction of the force on A towards B or away from B? c) what is the magnitude of the electric field at x = 0 cm and y = 0 cm?

A +2.00 nC point charge is at the origin, and a second -5.00 nC point charge is on the x- axis at x = 0.800m a.) Find the electric field (magnitude and direction) at each of the following points on the x- axis: i) x = 0.200 m; ii) x = 1.20 m; iii) x = -0.200m b.) Find the net electric force that the two charges would exert on the electron placed at each point in part (a).

6) a) Calculate the electric field 5.00 m from a 3.00 mC point charge. b) At this distance, what force does the field exert on a 2.00 μCcharge on the point charge?

Q3) Two identical conducting small spheres are placed with their centers 0.30 m apart. One is given a charge of 12.0 nC, and the other is given a charge of -18.0 nC. (a) Find the electric force exerted on one sphere by the other.

You hold a metal sphere that’s been positively charged, and yourfriend holds one too with the same charge. You approach one an-other and begin to feel apush back. You push harder, she pushes harder still, until you’re both pushing as hard as you can! Later, you estimate that you pushed with about 400N. If you guys can’t manage to bring the objects closer than 20cm, then what would you estimate the magnitudeof the charges on the spheres to be?