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TALLER 01 11 septiembre 2014.

Fsica para Ingeniera II

Profesor: Julio Cesar Quiceno

Electrostatic

1. Three point charges are located at the corners of anequilateral triangle, as shown in Figure. a) Calculatethe net electric force on the 7Ccharge. b) Calculatethe electric field at the position of the 2Ccharge dueto the 7Cand 4C charges. (c) Use your answer topart (b) to determine the force on the 2C charge.

2. A charged cork ball of mass 1 g is suspended on alight string in the presence of a uniform electric field,as shown in Figure. When E = (3i+ 5j) 105N/C,the ball is in equilibrium at = 37.0. Find (a) thecharge on the ball and (b) the tension in the strin.

3. A cone with base radius R and height h is located ona horizontal table. A horizontal uniform fieldE pen-etrates the cone, as shown in Figure. Determine theelectric flux that enters the left-hand side of the cone.

4. A conducting spherical shell of radius 15.0cmcarries anet charge of 6.40Cuniformly distributed on its sur-face. Find the electric field at points (a) just outsidethe shell and (b) inside the shell.

5. The line ag is a diagonal of a cube, as shown in Fig-ure. A point charge q is located on the extension ofline ag, very close to vertex a of the cube. Determinethe electric flux through each of the sides of the cubethat meet at the point a.

6. A positive point charge q of mass m is released fromrest in a uniform electric field E directed along the xaxis, as shown in Figure. Describe its motion.

7. A thin conducting plate 50.0 cm on a side lies in thexy plane. If a total charge of 4X108Cis placed on theplate, find (a) the charge density on the plate, (b) theelectric field just above the plate, and (c) the electricfield just below the plate.

8. A charge q1 = 2C is located at the origin, and achargeq2 = 6Cis located at (0, 3)m. (a) Find the to-tal electric potential due to these charges at the pointwhose coordinates are (4, 0)m.

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9. An electric dipole consists of two charges of equal mag-nitude and opposite sign separated by a distance 2a,as shown in Figure. The dipole is along the x axis andis centered at the origin. (a) Calculate the electric po-tential at point P. (b) Calculate V and Ex if point Pis located anywhere between the two charges.

10. Find (a) the electric potential and (b) the magnitudeof the electric field along the perpendicular central axisof a uniformly charged disk of radius a and surfacecharge density .

11. A disk of radius R has a nonuniform surface chargedensity = Cr , where C is a constant and r is mea-sured from the center of the disk. Find (by directintegration) the potential at P.

12. A spherical capacitor consists of a spherical conduct-ing shell of radius b and charge Qconcentric with asmaller conducting sphere of radius a and charge Q.Find the capacitance of this device.

13. Find the equivalent capacitance between points a andb for the group of capacitors connected as shown inFigure ifC1 = 5.00F, C2 = 10.0F,andC3 = 2.00F.

14. For the system of capacitors shown in Figure, find (a)the equivalent capacitance of the system, (b) the po-tential difference across each capacitor, (c) the chargeon each capacitor, and (d) the total energy stored bythe group.

15. An electric current is given by the expression I(t) =100sin(120t), where I is in amperes and t is in sec-

onds. What is the total charge carried by the currentfromt = 0tot= 1/240s?

16. A current density of 6X1013A/m2 exists in the atmo-sphere where the electric field (due to charged thun-derclouds in the vicinity) is 100V/m. Calculate theelectrical conductivity of the Earths atmosphere inthis region.

17. A 10V battery is connected to a 120 resistor. Ne-glecting the internal resistance of the battery, calculatethe power delivered to the resistor.

18. Calculate the power delivered to each resistor in thecircuit shown in Figure.

This questionnaire was extracted from the book Halli-day, Resnick, Walker, Fundamentals of Physics, 8 edi-tion.

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