A 2.45 g air-inflated balloon is given an excess negative charge, q¡ = -3.25 × 10-8 C, by rubbing it with a blanket. It is found that a charged rod can be held above the balloon at a distance of d = 7.20 cm to make the balloon float. Assume the balloon and rod to be point charges. The Coulomb force constant is 1/(4xe0) = 8.99 × 10º N-m²/C² and the acceleration due to gravity is g = 9.81 m/s².

A 8-g charged plastic sphere charged to 75 µC is on top of a plastic spring with spring constant k = 400 N/m, which has a relaxed length of 10 cm. You then place another charged object 1 cm above (not touching) the sphere. Now, the spring is 9.5 cm long. Find the charge on the new second object.

please help with questions 28,29,30

Two fixed positively charged balls (q 1 = 1 × 10-ºC; q 2 =?) are separated by a distance d = 0.3 m. If the Coulomb force between the two charges is F = 10-6N, then the charge q2 is equal to: (ke = 9 × 10° N.m²/C²) 10^-9 C 10^-8 C 10^-7 C 10^-2 C 10^-6 C

A conducting spherical shell has inner and outer radii r = 0.12 m and = 0.15 m, respectively. As shown in the figure, a concentric insulating sphere of radius r = 0.05 m is located inside the spherical shell. The insulating sphere has a charge of 10,7 nC uniformly distributed over its volume and the conducting shell has a charge of -2 nC. (Take Coulomb's constant as k 9GNm²/C2. Note that nC 10 °C, GN= 10' N) rb (c) Determine the magnitude of the electric field at point P, a distance rp = 0.10 m from the center of the insulating sphere, in N/C. A conducting spherical shell has inner and outer radii = 0.12 m and r = 0.15 m. respectively. As shown in the figure, a concentric insulating sphere of radius r. = 0.05 m is located inside the spherical shell. The insulating sphere has a charge of 10,7 nC uniformly distributed over its volume and the conducting shell has a charge of -2 nC. (Take Coulomb's constant as k = 9GNm²/C². Note that nC 10 °C, GN - 10°N) rb rc o. P (b) Calculate the…

A 0.01294 kg ball with a positive charge of 47.4 μC hangs from a light string right next to a large vertical metal plate (the metal plate is so large compared to the length of the string and ball consider it to be infinite in size).  How much surface charge density must the plate have to repel the ball so that the string makes and angle of 5.03 degrees from the vertical.  Give your answer to 3 significant figures and in units of nC/m/m (nanoCoulombs per meter squared: Blackboard has trouble with squred units).  Type in the units right after your numerical answer.

Suppose a speck of dust in an electrostatic precipitator has 8.0000 × 10+" protons in it and has a net charge of 2.00 nC (a very large charge fọr a small speck). How many electrons does the speck have? Include 5 significant figures in your answer. For this problem, use e = 1.6022 × 10¬1º C as the fundamental charge. n = number (5 significant figures)