- d– т т Figure P15.65

Three dots are resting on the vertices of a triangle. The sides of the triangle have a length of a = 0.68 m, as shown. Two of the dots (S1 and S3) have +6.5 µC charge, while the other (S2) has −6.5 µC charge. (a) Find the direction of the net force on the third dot (S3) in degrees counterclockwise from the +x-axis.   (b) Find the direction of the net force on the third dot (S3) when it is moved to the origin in degrees counterclockwise from the +x-axis.

Two small beads having positive charges q1 = 29q and q2 = q are fixed at the opposite ends of a horizontal insulating rod of length d = 1.50 m. The bead with charge q1 is at the origin. As shown in the figure below, a third small, charged bead is free to slide on the rod.   (a) At what position x is the third bead in equilibrium?x =  m(b) Can the equilibrium be stable?

(a) A physics lab instructor is working on a new demonstration. She attaches two identical iron spheres with mass m = 0.190 g to filaments of length L as shown in the figure. L. Both spheres have the same charge of 7.60 nC, and are in static equilibrium when 0 = 5.20°. What is L (in m)? Assume the filaments are massless. 0.31 (b) What If? The charge on both spheres is increased until each filament makes an angle of 0 = 10.4° with the vertical. If both spheres have the same electric charge, what is the charge (in nC) on each sphere in this case? 2.16E-8 Use the same reasoning as in part (a), only now, use the length found in part (a) and the new angle to solve for the charge. nC

Two small spheres of mass 215g are suspended from strings of length 1.1m that are connected at the same point. One sphere has charge Q=0.8uC , and the other has charge 2Q. In equilibrium the strings make angles 01 and 02 with vertical. Assume that 01 and 02 are small. Find the equilibrium distance r between the spheres. State your answers to nearest 0.01 cm. Take k=8.99x1o° Nm2/C2 and g=9.8m/s²

Two metal spheres of identical mass m 3.60 g are suspended by light strings 0.500 m in length. The left-hand sphere carries a charge of 0.885 μC, and the right-hand sphere carries a charge of 1.59 μC. What is the equilibrium separation between the centers of the two spheres? m =