Which of the following statements is true? . a. in an endothermic reaction, the energy of the products is the same as the energy of the reactants.. b. in an endothermic reaction, the energy of the products is less than the energy of the reactants.. c. in an exothermic reaction, the energy of the products is the same as the energy of the reactants.. d. in an exothermic reaction, the energy of the products is less than the energy of the reactants.

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.

What practical value did astronomy offer to ancient civilizations?

Find an expression for the electric field e⃗ at the center of the semicircle. hint: a small piece of arc length δs spans a small angle δθ=δs /r, where r is the radius. express your answer in terms of the variables q, l, unit vectors i^, j^, and appropriate constants.