Newton's third law with a pulley system and work/potential energy

[primarygun]

One question related to Newton's third law,
v
t p
u o
u o
It is a rope with a wheel,v.
If 50N is applied from u pulling towards the ground, what's the reaction force?
From o to p ?

Two questions related to work,
I think the force in the equation of work done is continuously applied,like weight, right?
And the object would not stop finally, right?

For the PE, a weight of 100N is lifted up by a man up to a height of 10m.
Why the force applied by the man continuously is 100N?
Isn't 100 N causing no effect on the weight as it is compensated by the mg of the weight, right?

 

[arildno]

"One question related to Newton's third law,
v
t p
u o
u o
It is a rope with a wheel,v.
"
What does this mean?

 

[ulli]

 

[primarygun]

How about these?
Two questions related to work,
I think the force in the equation of work done is continuously applied,like weight, right?
And the object would not stop finally, right?

For the PE, a weight of 100N is lifted up by a man up to a height of 10m.
Why the force applied by the man continuously is 100N?
Isn't 100 N causing no effect on the weight as it is compensated by the mg of the weight, right?