The uniform 60-kg crate c rests uniformly on a 10-kg dolly d. if the front casters of the dolly at a are locked to prevent rolling while the casters at b are free to roll, determine the maximum force p that may be applied without causing motion of the crate. the coefficient of static friction between the casters and the floor is μf=0.35 and between the dolly and the crate, μd=0.5.

One kind of e-book display consists of millions of very small spheres that float in a thin fluid layer between two conducting transparent plates. each sphere is black on one side and white on the other, and possesses an electric dipole moment directed from the white side to the black. when an electric field is applied between the plates, the spheres rotate so that their dipole moment lines up with the field. depending on the fields direction, either the black or the white sides of th espheres can be made visible.the dipole moment of the spheres can be modeled as two opposite charges of magnitude 3.5 x 10^-15 c, separated by a distancce of 100 micrometers (um). what is the maximum possible torque on a sphere if the electric field between the transparent plates is 4.0 x 10^5 n/c