A regular pentagon with sides of length l=10 cm and radius r=8.5 cm, has a charge at each vertex. Four of the vertices have charge 36 μC, and one has charge -17 μC. What is the magnitude of the electric field at the center of the pentagon in units of 106 N/C? Take k=9x109 Nm2/C2. (Hint: you can do this without angles or trigonometry if you use symmetry...) Your result must contain at least one figure after the decimal point and maximum of 5% of error is accepted in your answer.

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

Is the portion of the electromagnetic spectrum that has a frequency just above that of visible light.

69. air frictionthe velocity of the satellitea. decreases b. increases c. sometimes increases sometimedecreases d. no effect at all70. the unit of gravitational potential energy isa. jouté b. watt c. newtond. pascal71. which of the following is not influenced by a magneta. cobalt b. copper c. irond. nickel72. one joule of work done in one second by unit positive chargea.1 watt b.1 volt c.1 js d. none73. the most deviated colour of light after passing through a prisea. violet b. red c. green d. yellow4. a coin is placed below a beaker fill with water upto 12 cm isdisplaced by water isa. 9cm b.6cmс.3cmd.7cm