A 7 kg block is at rest on a table. The coefficient of static friction between the box and the table is 0.40 and the coefficient of kinetic friction is 0.10 . Then a 30 N horizontal force is applied to the box. What is the acceleration of the box? (Use 9.8 m/s/s for the acceleration due to gravity). Please hurr

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.