题目

一滑雪人与滑雪板的总质量为60kg，从长为100m、倾角为30°的斜坡顶端由静止开始匀加速下滑，经10s滑到了坡底。取g=10m/s2，求：1.滑雪人下滑的加速度；2.人与滑雪板所受的阻力（包括摩擦和空气阻力）。  答案： 1.2 m/s22.f＝mgsinθ－ma＝180N  解析:略 — Are you learning art now during your spare time? — No. I've stopped _____ Chinese medicine instead. [     ]A. to learn B. learning C. learn D. studying