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school physics question
 

offline pepe from Madrid (Spain) on 2010-02-10 13:39 [#02366040]
Points: 252 Status: Lurker



anyone good at physics can help me?


 

offline mohamed from the turtle business on 2010-02-10 13:50 [#02366044]
Points: 31145 Status: Regular | Show recordbag



ME! i've had 2/10 thru my whole school career


 

offline pepe from Madrid (Spain) on 2010-02-10 14:24 [#02366054]
Points: 252 Status: Lurker



A ladder of 6m long rests along a smooth wall at 25" from
the wall. The floor on which the ladder rests is rough.
Standing half way up the ladder is a woman of mass 75kg.
Assuming the ladder does not slip. Determine by graphical
solution

a. The reaction between the ladder and the wall.
b. The reaction of the floor and the ladder.


 

offline mohamed from the turtle business on 2010-02-10 14:32 [#02366061]
Points: 31145 Status: Regular | Show recordbag



hold on i've got to go to the toilette first

please the others don't post before me


 

offline JivverDicker from my house on 2010-02-10 14:56 [#02366062]
Points: 12102 Status: Regular | Followup to pepe: #02366054



mgacosα + F2asinα = R2acosα

F is friction
R is the normal reaction against the ground


 

offline vlari from beyond the valley of the LOLs on 2010-02-10 14:58 [#02366064]
Points: 13915 Status: Regular



i used to be good at this, but then i met dave


 

offline pepe from Madrid (Spain) on 2010-02-10 15:10 [#02366066]
Points: 252 Status: Lurker



o safe

pepé require graphical solution bre's

safe


 

offline pulseclock from Downtown 81 on 2010-02-10 15:13 [#02366067]
Points: 6015 Status: Lurker | Followup to pepe: #02366066



i think it's SAFE to assume you're cwnt

or Ali G


 

offline mohamed from the turtle business on 2010-02-10 19:31 [#02366106]
Points: 31145 Status: Regular | Show recordbag



*head explodes*


 

offline gingaling from Scamworth (Burkina Faso) on 2010-02-11 07:18 [#02366168]
Points: 2281 Status: Lurker



peepee i dont quite get it, but as i read it, the ladder
doesnt slip so there is no reaction, just a 75kg woman
standing half way up a ladder, is she putting up a bird box?


 

offline Terence Hill from Germany on 2010-02-11 07:28 [#02366169]
Points: 2070 Status: Lurker



he wants a graphical solution dude.


 

offline gingaling from Scamworth (Burkina Faso) on 2010-02-11 09:17 [#02366185]
Points: 2281 Status: Lurker | Followup to Terence Hill: #02366169



graphical representation

i hope this is usefull, feel free to use it as an
informative and decorative classroom learning aids.


 

offline Terence Hill from Germany on 2010-02-11 09:41 [#02366187]
Points: 2070 Status: Lurker | Followup to gingaling: #02366185



i take three trucker hats.


 

offline gingaling from Scamworth (Burkina Faso) on 2010-02-11 10:08 [#02366192]
Points: 2281 Status: Lurker | Followup to Terence Hill: #02366187



sold.


 

offline vlari from beyond the valley of the LOLs on 2010-02-11 10:33 [#02366207]
Points: 13915 Status: Regular



i'll take one skateboard


 

offline gingaling from Scamworth (Burkina Faso) on 2010-02-11 10:54 [#02366212]
Points: 2281 Status: Lurker | Followup to vlari: #02366207



sold.


 

offline dave_g from United Kingdom on 2010-02-11 11:06 [#02366215]
Points: 3372 Status: Lurker



Ahh fond memories of doing this crap from school....

Off the top of my head, you probably want to check
this.......

You use Newton's laws to work out forces (F=ma)
Moman is m=75kg, a=g=9.8 (acceleration of gravity, g)
Force down is 735N.
Now work out the horizontal and vertical components on the
ladder:
Need to do polar <-> cartesian conversion, i.e.

x = F cos @, y = F sin @
where @ is theta (use your imagination)

In your case, @ = 25 degrees
X is force acting horizontally, Y is force acting
vertically.

x= 666N
y = 310N

use pythagoras to check:
z = sqrt (x^2 + y^2) = 735. OK

That should get you going....

Solve graphically means you have to draw all the forces on a
diagram to show you understand what's going on.

Hope that helps.


 

offline -crazone from smashing acid over and over on 2010-02-11 11:06 [#02366216]
Points: 11234 Status: Lurker | Show recordbag



c) she hits the moon.


 


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