A student is trying to solve the following problem by the tile shown

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

If the new moon happens on january 15th, what shape will it be on february 6th?

Which of these is constant for all types of electromagnetic radiation in a vacuum? select one: a. wavelength b. frequency c. photon energy d. amplitude e. velocity