题目

质量分别为m1和m2的两个小物块用轻绳连接，绳跨过位于倾角＝30°的光滑斜面顶端的轻滑轮，滑轮与转轴之间的摩擦不计，斜面固定在水平桌面上，如图所示。第一次，m1悬空，m2放在斜面上，用t表示m2自斜面底端由静止开始运动至斜面顶端所需的时间。第二次，将m1和m2位置互换，使m2悬空，m1放在斜面上，发现m1自斜面底端由静止开始运动至斜面顶端所需的时间为。求m1与m2之比。猜谜语。( ) (1) It's small and thin. A. It's a panda.( ) (2) It has long ears and a short tail. B. It's an elephant.( ) (3) It has a long nose. C. It's a goldfish.( ) (4) It's black and white. It's fat. D. It's a mouse.( ) (5) It has a long tail and big eyes. E. It's a rabbit.