1. The problem statements, all variables and given/known data 1. A plane leaves the ground and rises at an angle of 25º. If its speed relative to the ground is 210 mph, what is its speed relative to the air? A. 232 mph B. 210 mph C. 190 mph D. 89 mph 2. What happens to water molecules when they go from a solid to a liquid? A. They slow down as ice melts. B. Nothing. C. They speed up as ice melts. D. They get really cold as ice is formed. 2. Relevant equations I'm not sure if any equations are necessary for either of the questions, but maybe vair = vground - vwind 3. The attempt at solutions I think the answer to the first question is B, because the air has no defined velocity and thus there should be no difference in relative velocity whether it's on the ground or in the air. However, I'm not sure if the fact that it rose to the air means that a vertical component is added to the plane's velocity, which would make the resulting velocity 210mph/cos(25), equivalent to 232mph (answer A.) As for the second question, I don't think that C is true, because water molecules do not increase in temperature, and therefore speed, during change in state. What I learned in Chemistry is that the energy used during state change is used for breaking their intermolecular bonds. So I'm leaning towards B, but not exactly "nothing" is happening to the water molecules. Am I missing something?