Someone gimme the answer lol

When a septic tank backs up a goes in to clean it out

Aroller coaster is traveling at 13 mi./s when you purchase a hill that is 400 m long and down the hill exonerate at 4.0 m/s squared what is the final velocity of the posterior found your answer to the nearest number

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?