Calculate the mechanical advantage if a machine allows you to move a 60 newton rock by only exerting 15 newtons of force.

What is special about a dc circuit ?

The diagram shows four locations in the electric field of a positive point charge m. at which location is the electric potential the greatest.

At a certain instant after jumping from the airplane a, a skydiver b is in the position shown and has reached a terminal (constant) speed vb = 52 m/s. the airplane has the same constant speed va = 52 m/s, and after a period of level flight is just beginning to follow the circular path shown of radius ρa = 2330 m. (a) determine the velocity and acceleration of the airplane relative to the skydiver. (b) determine the time rate of change of the speed vr of the airplane and the radius of curvature ρr of its path, both as observed by the nonrotating skydiver.