Un avion descrie un semicerc cu raza de 100 metri, iar delta t=4 s.
a)desenati traicetoria vectorului de pozitie initial si final fata de centrul cercului si vectorul deplasare
b)calculati valoarea vectorului viteza medie
c)presupunand ca si-a mentinut viteza constanta , calculati viteza momentana a avionului

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.

If the area of a square has increased by a factor of 16, by how much has each side increased?

Which of the following is a measure of the amount of light a star directly emits?               a.  luminosity    b.  intensity    c.  wavelength    d.  brightness