A charge of 661 nC and mass m = 11 g is suspended from a 1.1 m long string. When the string makes an angle of 16o to the vertical, the charge is in equilibrium. The charge is acted upon by another charge of 622 nC fixed in space. What is the tension in the string?

The space between two 15-in.-long concentric cylinders is filled with glycerin (viscosity = 8.5 × 10-3 lb·s/ft2). the inner cylinder has a radius of 1 in. and the gap width between cylinders is 0.1 in. determine (a) the torque and (b) the power required to rotate the inner cylinder at 180 rev/min. the outer cylinder is fixed. assume the velocity distribution in the gap to be linear.