题目

 如图所示，半径为R的圆桶内有一质量为m的物体贴着内壁跟随桶以角速度ω作匀速圆周运动，此时桶壁受到的压力的大小为          ，物体与桶壁的静摩擦力为          。  答案： __ mRω2__ ____ mg ____    —Do you know the man _______ is talking with our English teacher?—Oh, he must be Lin Tao's father. He was looking for Lin Tao just now. A．whomB．whichC．whoseD．who