If anyone could answer even just one of the questions below I would really appreciate it. 1. Why do cars get better gas mileage at constant speed than they do with a lot of accelerating? 2. The space arm works in weightless conditions (actually called microgravity conditions). Why must it still be made strong? 3. Albert Einstein, in his special theory of relativity, prediced that nothing with mass will ever be able to reach the speed of light. Explain how Newton's 2nd law (F=ma) supports Einstein's prediction. 4. Why does oiling the contact areas between two surfaces reduce the amount of friction between those surfaces? 5. Polishing the contact area between two surfaces initially decreases friction but when the surfaces are extremely smooth and flat, friction increases. Explain why. I have a rough idea for numbers 3 4 and 5, but I want to hear some suggestions on this. Thanks in advance to anyone who helps.