Xiaoyue uses the pulley block as shown in the figure to lift the object A with a gravity of 600N at a constant speed of 2 m within 10s. As we all know, the tension at the free end of the rope is 200 Newton. (1) As can be seen from the figure, the pulley block is supported by four ropes, so F= 14(G +G), then g = 4f-g = 4× 200 n-600 n = 200 n;

(2)W is useful = GH = 600 N× 2m =1200J;

(3)s=4h=4×2m=8m

The work done by abortion is W total =Fs=200N×8m= 1600J.

Then P=W, and the total t =1600j10s =160w.

(4)η=W Total amount of useful W×100% =1200J1600J×100% = 75%.

(5)F = 14×(G+G)= 14×(800N+200n)= 250n。

Answer: (1) The total weight of the moving pulley is 200 N;

(2) How much useful work has Abortion done is1200J; ;

(3) the power of abortion is160 w;

(4) The mechanical efficiency of pulley block is 75%;

(5) The tensile force shall be 250 N. 。