题目

We already know the fastest, least expensive way to slow climate change: Use less energy. With a little effort, and not much money, most of us could reduce our energy diets by 25 percent or more—doing the Earth a favor while also helping our wallets．        Not long ago．My wife, PJ, and I tried a new diet—not to lose a little weight but to answer an annoying question about climate change．Scientists have reported recently that the world is heating up even faster than predicted only a few years ago, and that the consequences could be severe if we don’t keep reducing emissions（16分）汽车发动机的额定功率为60KW,汽车的质量为5t,汽车在水平路面上行驶驶时，阻力是车重的0.1倍，g=10m/s2 。（1）汽车保持额定功率不变从静止起动后，①汽车所能达到的最大速度是多大？②当汽车的加速度为2m/s2时速度多大？③当汽车的速度为6m/s时的加速度？（2）若汽车从静止开始，保持以0.5 m/s2的加速度做匀加速直线运动，这一过程能维持多长时间？