题目

—I tried many ways to solve the problem, butof them worked. —Never give up. You'll surely make it. A . all B . none C . neither 答案：B10．水平地面上有一个木箱，其质量为50kg，推着它运动时，受到的摩擦力是自身重力的2倍，求：（1）木箱的重力；（2）木箱所受摩擦力的大小．