Find the man's tension pulling the rope

[Adam Hanns F A Cong]

Homework Statement

Ignore the mass of the rope and the pulley,frictional force between the man and the board, the board and ground. Now the man is pulling the rope in order to make him and the board move to the right uniformly. Find the man's tension of pulling the rope.
I got a wrong answer.
Could you please explain the pulley's principle in moment of the force or (angular) momentum?

Relevant Equations

The gravity G_1 of the man is 600N,the gravity G_2 of the board is 400N. The coefficient of the kinetic friction μ both between the man and the board,the board and ground is 0.2.

The elastic force of the board,N=G_1+G_2=1000N.
The kinetic friction f=μN=200N.
The tension T=f=200N.

 

[PeroK]

You need to show the forces on your diagram.

PS have you heard the term mechanical advantage?

 

[Adam Hanns F A Cong]

You mean like it? Forgive my ignorance,please. I may not know term mechanical advantage. Do you mean the next fig.2? I learnd that it comes from the level principle,and the level seems that it comes from the moment force or (angular) momentum,but I don't know how to find the momentum or radius vector.

 

[PeroK]

Tension is a two-way force in a rope.

A lever is not the only example of mechanical advantage. Sometimes you can use a pulley system!

 

[Adam Hanns F A Cong]

Thank you.
I learned pulley system two years ago at junior high,but I am not good analyse it.
All in all, thanks for your help!