During first half of a journey by a body it travel with a speed of 40km/hr and in the next half it travels with a speed of 20 km/hr .Calculate the average speed of the whole journey.

Which notation is used to represent an alpha particle? a. b. c. d.

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.

The mantle is made up of which structural zones?