A teacher place a 75-pound box of stationery on a ramp having an angle of inclination 60 degree to the horizontal and pulls the box up the ramp using a wire harness attached to the end by exerting a force of 80 pounds at an angle of zero degree to the ramp. What is the force of friction restricting the movement of a box if the teacher pulls it up the ramp at a constant speed? Please explain your answer step by step and draw a graph on a single cartesian plane in your note. *

To understand the behavior of the electric field at the surface of a conductor, and its relationship to surface charge on the conductor. a conductor is placed in an external electrostatic field. the external field is uniform before the conductor is placed within it. the conductor is completely isolated from any source of current or charge. part a: which of the following describes the electric field inside this conductor? it is in the same direction as the original external field.it is in the opposite direction from that of the original external field.it has a direction determined entirely by the charge on its surface.it is always zero. part b: the charge density inside the conductor is: 0non-zero; but uniformnon-zero; non-uniforminfinite part c: assume that at some point just outside the surface of the conductor, the electric field has magnitude e and is directed toward the surface of the conductor. what is the charge density η on the surface of the conductor at that point? express your answer in terms of e and ϵ0