(2) according to the meaning of the question, w is always =GAh+G moving h.

That is, 340J= 1400N×0.2m+G ×0.2m, then G = 300N.

(3) People's pressure on the ground: F people = 600 n-f';

It can be obtained by f ′× OH = Fe× OE and Fe = oh. f′/OE = 2 f′。

From the condition of force balance, we can know that T+ G motion = 2 FE? That is T=4 F'- G dynamics.

Therefore, the pressure of counterweight A on the ground is? FA = 1400n-4 F '+300n = 1700n-4 F '

By p =PA? F people /S people =? FA /SA

F' = 250n brings in the data solution.