Pls write out & show work for all thank you!

1. Two train cars roll without friction along a level track. One car has mass 200,000 kg and rolls at +4.5 m/s and the other has mass 120,000 kg and rolls at - 2.5 m/s. What is the speed and direction (right or left) of both cars after they collide and stick together? Let right = + 2. A satellite orbits a planet at a radius of 7.82 X 10 m. The mass of the planet is 8.91 X 1024 kg. What is the satellite's speed? 3. Using the diagram below, calculate the emitted photon wavelength for the 3 - 1 electron transition for the Hydrogen atom. Write this wavelength in nanometers (nm). No credit if you only write down energy. - n = 0o n = 4 -1.51 n = 3 -3.40 n = 2 Energy (eV) Photon -13.6 n = 1 2005 Brooks/Cole - Thomson