The power output of a laser is measured by its wattage, the number of joules of energy it radiates per second (1 w = 1 j s-1). a 300-mw krypton laser produces a beam of red light with a wavelength of 676.4 nm (6.764×10-7 m). (a) calculate the energy carried by each photon. (b) calculate the number of photons emitted by the laser per second.

Two manned satellites approaching one another at a relative speed of 0.550 m/s intend to dock. the first has a mass of 2.50 ✕ 103 kg, and the second a mass of 7.50 ✕ 103 kg. assume that the positive direction is directed from the second satellite towards the first satellite. (a) calculate the final velocity after docking, in the frame of reference in which the first satellite was originally at rest.(b) what is the loss of kinetic energy in this inelastic collision? (c) repeat both parts, in the frame of reference in which the second satellite was originally at rest. final velocity(d) loss of kinetic energy = ?