如图 5.6.4 所示, 为一皮带传动装置,右轮半径为 r , a 为它边缘上一点;左侧是一轮轴,大轮半径为 4r ,小轮半径为 2r , b 点在小轮上,到小轮中心的距离为 r 。 c 点和 d 点分别位于小轮和大轮的边缘上。若传动过程中皮带不打滑,则 ()。 1 a 点和 b 点的线速度大小相等 2 a 点和 b 点的角速度大小相等 3 a 点和 c 点的线速度大小相等 4 a 点和 c 点的向心加速度大小相等
【简答题】—Excuse me, sir. Would you do me a favor? —Of course, what is it? —I ______ if you could tell me how to fill out this form. A) has wondered B) was wondering C) would wonder D) did wonder