一個物理力學問題： 有一個斜面放在水平的卓上，斜面與水平成50度，有一個100N的力，垂直的壓在斜面上，這樣的話, 斜面會向水平方向移動，那麼即是有多少力從水平方向推動斜面？

If the force is applied in direction as given in your diagram, the force component pushing the wedge to move horizontally will be zero.

But I wonder if you have misinterpret the question. It says that the force is "...垂直的壓在斜面上..", it may mean the force is perpendicular to the slant surface of the wedge. In that case, the component of force pushing the wedge to the right is 100.sin(50) N = 76.6 N

斜面會會不會向水平方向"移動"？仍有未知數
但從水平方向推動斜面的分力"理論上"是100N*sin(50度)