Ladder leaning on wall, person on ladder.

[astrologically]

http://ronney.usc.edu/AME101/AME101-F14-PS3.pdf

number 1 in the link tyty

 

[Matterwave]

Please use the template provided, and also show what you did to try to solve the problem.

 

[astrologically]

ohhh my bad

 

[astrologically]

uhh how do i get the template now?

 

[Matterwave]

You can start a new thread in another window and just copy and paste the template over to here.

 

[astrologically]

anyways naming the point of where ladder touching the wall 1 and the part where the ladder touches the ground 2 I have
Fn₁ will the wall's force on the ladder and Fn₂ will be the ground's force on the ladder. Ffr₁ is friction of where 1 is and Ffr₂ is friction force of where 2 is.

Sum of Fx= Fn₁ - Ffr₂=0 Fn₁=Ffr₂
Sum of Fy=Ffr₁+Fn₂=0=Ffr₁+Fn₂-150

then I'm not sure what to do.

 

[astrologically]

hmm i did try your way but it's not giving me the template anymore

 

[astrologically]

ahh found it

Homework Statement

to find all unknowns.
mu₂=0.24
distance from person to 1 is 3ft
distance form person to 2 is 7ft
horizontal distance is 4ft
mg of individual is 150lbf

Homework Equations

torque=fd

The Attempt at a Solution

Sum of Fx= Fn1 - Ffr2=0 Fn1=Ffr2
Sum of Fy=Ffr1+Fn2=0=Ffr1+Fn2-150[/B]

 

[Matterwave]

EDIT: looks like you found it.

I see that your relevant equations has a torque equation in it, and yet you did not attempt to use it in your solution. Why is that?

 

[astrologically]

oh sorry I did try taking moments in both point 1 and point 2 and turned out with nothing.

Taking moment at point 1.
M₁=-(3(150))+Fn₂(10)

Taking moment at point 2
M₂=-(Fn₁(10)+(7(150))

Taking moment at where the person is at
M₃=-Fn₁(3)+Fn₂(7)

From there on I'm not sure what to do

 

[Matterwave]

Your moment equations are incorrect because they don't take into account the angle between the force and the radius displacement. The correct equation for torque is $\vec{\tau}=\vec{r}\times\vec{F}$

Also, at point 1 (and at point 2), there are 2 different forces, the frictional force and the normal force. You have to take both of them into account.