(20 10? Workers use machinery to lift solids A and B in water, and the lever can rotate freely in the vertical plane. When the object A is lifted at a constant speed,

The force analysis of each object is as follows:

G people =m people g=70kg× 10N/kg=700N.

GA = mAg = 580kg× 10N/kg = 5800n

GB = mBg = 820kg× 10N/kg = 8200n

F float A=ρ water GVA =1.0×103kg/m3×10n/kg× 400×10-3m3 = 4000n.

F float B=ρ water gvb =1.0×103kg/m3×10n/kg× 600×10-3m3 = 6000n.

According to the stress analysis, we can get the following results:

Personnel:

700n+fa 1′= n 1①

700 degrees north latitude+Fa2 ′ = N2 ⑥

Rod:

FA 1×0A=FB 1×0B？ ②

FA2×0A=FB2×0B？ ⑦

Wheels:

FB 1'= F pull A+G move 2③

FB2'=F，B+G，2，8。

Things:

5800N=4000N+F pull A4

8200N=6000N+F pull B 4

To solve this problem, you must:

∫n 1 = 1200 N2 = 1300n

FA 1'= 500N from ①.

Substitute f from ④ into ③ by pulling A= 1800N.

FB 1'= 1800n+G Substitute 2 into ②.

500×OA= 1800N+G moves 2×OB ⑤.

In the same way ⑧ ⑨ Solution:

600×OA=2200N+G Mobile 2× OB Indication

From ⑤ ⑩ ratio: g moving = 200 n.

Answer: (1) The human gravity is 700N, the gravity of object A is 5800N, the gravity of object B is 8200N, the buoyancy of A is 4000N, and the buoyancy of B is 6000 N. 。

(2) The gravity of the moving pulley is 200 n. 。