Two red blood cells each have a mass of 9.05×10−14 and carry a negative charge spread uniformly over their surfaces. The repulsion arising from the excess charge prevents the cells from clumping together. One cell carries −2.70 pC and the other −2.90 pC, and each cell can be modeled as a sphere 3.75×10−6m in radius. If the red blood cells start very far apart and move directly toward each other with the same speed, what initial speed would each need so that they get close enough to just barely touch? Assume that there is no viscous drag from any of the surrounding liquid.

One particle has a mass of 3.71 x 103 kg and a charge of +7.56 μC. A second particle has a mass of 7.17 x 103 kg and the same charge. The two particles are initially held in place and then released. The particles fly apart, and when the separation between them is 0.177 m, the speed of the 3.71 x 103 kg-particle is 126 m/s. Find the initial separation between the particles. V1,B V2,B 92 92 91 Number i 0.011 Units m "B 91

An infinite line of positive charge lies along the y axis, with charge density A = 1.10 µC/m. A dipole is placed with its center along the x axis at x = 21.0 cm. The dipole consists of two charges ±10.0 µuC separated by 2.00 cm. The axis of the dipole makes an angle of 25.0° with the x axis, and the positive charge is farther from the line of charge than the negative charge. Find the net force exerted on the dipole.

Two small particles have charges Q₁ = +4.0 μC and Q₂ = -7.0 μC. The particles are conducting and are brought together so that they touch. Charge then moves between the two particles so as to make the excess charge on the two particles equal. If the particles are then separated by a distance of 5.4 mm, what is the magnitude of the electric force between them?

Four identical charged particles (g = +10.1 µC) are located on the corners of a rectangle as shown in the figure below. The dimensions of the rectangle are L = 64.2 cm and W = 14.6 cm. L (a) Calculate the magnitude of the total electric force exerted on the charge at the lower left corner by the other three charges. (b) Calculate the direction of the total electric force exerted on the charge at the lower left corner by the other three charges. ° (counterclockwise from the +x-axis)

Calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 10.0 g. Silver has 47 electrons per atom, and its molar mass is 107.87 g/mol. Imagine adding electrons to the pin until the negative charge has the very large value 1.00 mC. How many electrons are added for every 109 electrons already present?

Two identical conducting spheres, fixed in place, attract each other with an electrostatic force of 0.140 N when their center-to-center separation is 63.8 cm. The spheres are then connected by a thin conducting wire. When the wire is removed, the spheres repel each other with an electrostatic force of 0.0403 N. Of the initial charges on the spheres, with a positive net charge, what was (a) the negative charge on one of them and (b) the positive charge on the other? (Assume the negative charge has smaller magnitude.)

One particle has a mass of 3.71 x 10‍3 kg and a charge of +7.56 µC. A second particle has a mass of 7.17 x 103 kg and the same charge. The two particles are initially held in place and then released. The particles fly apart, and when the separation between them is 0.177 m, the speed of the 3.71 x 103 kg-particle is 126 m/s. Find the initial separation between the particles. V1,B V2,B 92 92 91 Number i Units "B 91

Three identical metallic conducting spheres carry the following charges: q1 = +4.60 μC, q2 = +1.80 μC, and q3 = −1.60 μC. The spheres that carry the charges q1 and q2 are brought into contact. Then they are separated. After that, one of those two spheres is brought into contact with the third sphere that carries the charge q3; those two are then separated as well. How many excess (or deficiency) electrons make up the final charge on the third sphere?

Two chloride ions and two sodium ions are in water, the “effective charge” on the chloride ions (Cl−) is −2.00 × 10−21 C and that of the sodium ions (Na+) is +2.00 × 10−21 C. (The effective charge is a way to account for the partial shielding due to nearby water molecules.) Assume that all four ions are coplanar.             where a = 0.280 nm, b = 0.760 nm, and c = 0.460 nm.         What is the direction of electric force on the chloride ion in the lower right-hand corner in the diagram? Enter the angle in degrees where positive indicates above the negative x-axis and negative indicates below the positive x-axis.   °         Prev