no, it not useless. we still learn Bohr's model in HS n dats almost 200 yr old! while there may be new models, previous one is good for explaining the basics. it is also useful to learn previous model n see how our understanding improves over time.
With a 30 mph head wind it takes the plane 18.52 hours to fly 5000 miles. ANSWER 2: With a 30 mph tail wind it takes the plane 15.15 hours to fly 5000 miles.
