Ellie has a friend, Jack, that lives on a planet orbiting a star that is 20 light years away. On the night of her high school prom when Ellie is 17, she uses a radio telescope to send Jack one of her prom pictures (we will not speculate on her motives). Radio waves travel at the speed of light. Jack gets the picture and immediately uses his own radio telescope to send his own picture of his recent dinner date back to Ellie (again, let's not speculate ...). How old is Ellie when she gets Jack's picture?

Oxygen undergoes an isentropic expansion from 120 degree c and 280 kpa absolute to 140 kpa absolute. determine the final temperature of the oxygen and the amount of work per kg of o_2 produced in the process if it is adiabatic.

Infrared radiation has wavelengths that are shorter than visible light is part of the visible light spectrum has wavelengths that are longer than visible light has the same wavelengths as ultraviolet radiation

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 = ?