What is the wavelength and frequency of a photon emitted by transition of an electron from a n- orbit to a n-1 orbit'?

Find v(t), given acceleration a(t)=7j and initial velocity v(0)=k

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

Patricia is trying to compare the average rainfall of new york to that of arizona. a comparison between these two states for the months of july through september would best be measured in