物块重P，置于水平面上，静滑动摩擦系数为<img src="/Image1/00/000dfe3d4ebebb07cce2f79ae95c7d93.png" />。在物块上施加一倾角为α的拉力<img src="/Image1/24/2497c91b5efec3db71056afa70a953d8.png" />，则物块是否平衡取决于（）。 <img src="/Image1/40/40f92ff0e26fe392e6ccd92e6b670c66.png" /><br>A:<img src="/Image1/77/777fd5d0a59de9d95b52a70a022142a4.png" />，<img src="/Image1/24/2497c91b5efec3db71056afa70a953d8.png" />合力的大小<br>B:全反力的<img src="/Image1/78/785b8fbdf1712deda6ac1685495ba41c.png" />大小<br>C:<img src="/Image1/77/777fd5d0a59de9d95b52a70a022142a4.png" />，<img src="/Image1/24/2497c91b5efec3db71056afa70a953d8.png" />合力作用线的方位<br>D:不能判定