Maximum force that we can exert without breaking the rope?

[NeoPhoenix]

Homework Statement

If we want to pull a block with a weight of 5N attached to a rope that is just able to resist 20N. What is the maximum force that we can exert without breaking the rope? xD

Homework Equations

Fnet (in y) = ma = F (applied force) - W (weight)

The Attempt at a Solution

What I think is that: if the rope will just resist 20, and we already know that the weight of the block is 5N, then we should apply a 15N force right ?

 

[rock.freak667]

You want the net force to be less than or equal to 20N. Knowing W=5N, what is the applied force you should apply?

 

[NeoPhoenix]

actually, this is a problem that I had on a test some days ago...I think that was the question in fact. What force I should apply ?...

 

[rock.freak667]

actually, this is a problem that I had on a test some days ago...I think that was the question in fact. What force I should apply ?...

The maximum net force is 20N, using your relevant equation, what would the applied force?

 

[NeoPhoenix]

25n ?

 

[rock.freak667]

25n ?

That seems correct.

 

[NeoPhoenix]

thanks xD