動滑輪施力的方向與物件移動的方向是否相同?

It depends on which situation you are referring.
See:
http://en.wikipedia.org/wiki/Movable_pulley
Theory of operation






圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Pulley0.png/67px-Pulley0.png


Diagram 1 - A basic equation for a pulley: In equilibrium, the force F on the pulley axle is equal and opposite to the sum of the tensions in each line leaving the pulley, and these tensions are equal.






圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/5/52/Pulley1.png/71px-Pulley1.png


Diagram 2 - A simple pulley system - a single movable pulley lifting a unit weight. The tension in each line is half the unit weight, yielding an advantage of 2.






圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/c/cd/Pulley1a.png/75px-Pulley1a.png


Diagram 2a - Another simple pulley system similar to diagram 2, but in which the lifting force is redirected downward.






圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/6/62/Polispasto2.jpg/75px-Polispasto2.jpg


A practical compound pulley corresponding to diagram 2a.



I hope I can help.

滑轮是一种简单机械，由若干个绕有线绳的圆轮组成，是杠杆的变形。滑轮的中心称为轴，拉动线绳时，滑轮沿轴转动。按滑轮工作时轴的位置是否移动，可将滑轮分为定滑轮和动滑轮，多个滑轮组成的机械称为滑轮组。

动滑轮的功能除了改变力的方向之外，也降低了施力的的大小，其代价是必须施力较长的距离以保持能量守衡。