(20 10? Yingkou) is the structural schematic diagram of the lifting device of the water rescue boat. During the salvage process, the ship will sink into a seal deep underwater.

(1) According to the condition that an object floats in water, it is concluded that F float =G object, then △F float =G object =m object G,

So the increased displacement is 200 t;

(2) The number of rope segments on the moving pulley is 4,

∴s=4h=4× 1m=4m，

Then the pulling force will do work.

w total = Fs = 106n×4m = 4× 106？ j；

(3) Gravity of the container: G=mg=2× 105? kg× 10N/kg=2× 106？ n，

The useful work done by the extraction container: w Useful = GH = 2×106n×1m = 2×106j;

Mechanical efficiency: η=W Total amount of useful W×100% = 2×106j4×106j×100% = 50%;

(4) When the goods are in the water, the pulling force F= 14(G +G wheel -F floating), and when they are completely out of the water, the pulling force F= 14(G +G wheel).

Therefore, when the goods leave the water completely, the pulling force of the moving pulley on the container increases, and the useful work increases, while the extra work of the pulley block remains unchanged, which increases the mechanical efficiency of the pulley block.

Answer: (1) Before the salvage ship lifted the container, the displacement of the container increased by 200 t after it was completely out of the water;

(2) After the container comes out of the water completely, lift it at a constant speed1m.. Given that the cable force at this time is l06N, the work done by tension F in this process is 4× 106? j；

(3) The mechanical efficiency of the pulley block of the lifting device is 50%;

(4) The mechanical efficiency of the pulley block is increased in the process of the container discharging water and completely discharging water.