Why is it helpful to cross my organisms

Plz mark brainliest 30 points1) find the momentum of a 12 kg snowball that is rolling with a velocity of 9 m/s.2) an 8 ball with a mass of .5 kg is sitting at rest. it is hit by the cue ball (1 kg) traveling at 2.5 m/s. if the cue ball is at rest after the collision, how fast is the 8 ball traveling after the collision? 3) two football players are running toward each other. if the offensive player is 75 kg and is running 8 m/s, how fast must the 60 kg defensive player run in order for the two players to hit and stop?

The diagram below shows the different phase transitions that occur in matter. which arrow represents the transition in which dew is formed?

Calculate the energy required to ionize a hydrogen atom to an excited state where the electron is initially in the n = 5 energy level. report your answer in kilojoules