John and Haven move a large bookcase from the bedroom to the living room. The bookcase has a mass of 45 kg. They apply a force of 300 N to move the bookcase 8 m. It takes them 20 seconds to move the bookcase. How much work do they do to move the bookcase?

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?

Does anyone know how to solve this problem? i really need . i made an attempt but i just cant get it. a metal rod is 25.000 cm long at 25.0 degrees celsius. when heated to 102.0 degrees celsius, it is 25.054 cm long. what is the coefficient of linear expansion for this metal.

True or false graphs must include scales that increase by the same amount