Kimio
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anyone know where this question is from???

A ladder AB has mass M and length 6a.

The end A of the ladder is on rough horizontal ground.

The ladder rests against a fixed smooth horizontal rail at the point C.

The point C is at a vertical height 4a above the ground.

The vertical plane containing AB is perpendicular to the rail.

The ladder is inclined to the horizontal at an angle a, where sin a= 4/5,, as shown in Figure 1.

The coefficient of friction between the ladder and the ground is u.


The ladder rests in limiting equilibrium.

The ladder is modelled as a uniform rod.

Using the model,

(a) show that the magnitude of the force exerted on the ladder by the rail at C is 9Mg/25

(b) Hence, or otherwise, find the value of mu.
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spinningtop
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Not certain, but it looks very similar to some of the questions here: https://mathsmartinthomas.files.word...tics-pastq.pdf
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Hallouminatus
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Ladder questions like this are ubiquitous. What makes this one a bit unusual is that the ladder rests against a rail rather than a wall. Why do you need to know where it's from?
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scoobiedoobiedoo
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Did you ever find out where this question is from I had in my recent paper and I just want to see the solutions as I keep getting 9Mg/20

But when I model the rod as non uniform I get 9Mg/25.

And now I'm a bit paranoid about what mu could be 🥲
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Troyking221
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Was there a diagram for this question
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scoobiedoobiedoo
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Name:  USER_SCOPED_TEMP_DATA_MSGR_PHOTO_FOR_UPLOAD_1616102095945_6778423485431368406.jpeg
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Well I worked it out I had a diagram in my question but it never stated 4a as a height
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POP977NOW
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(Original post by scoobiedoobiedoo)
Name:  USER_SCOPED_TEMP_DATA_MSGR_PHOTO_FOR_UPLOAD_1616102095945_6778423485431368406.jpeg
Views: 104
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Well I worked it out I had a diagram in my question but it never stated 4a as a height
good
Last edited by POP977NOW; 1 month ago
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dm999
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That's correct. 18/49
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FaccoyKazz
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(Original post by scoobiedoobiedoo)
Name:  USER_SCOPED_TEMP_DATA_MSGR_PHOTO_FOR_UPLOAD_1616102095945_6778423485431368406.jpeg
Views: 104
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Well I worked it out I had a diagram in my question but it never stated 4a as a height
hello, thanks so much for working through this publicly i was so stuck! would you be able to explain to me your horizontal forces because i couldn’t get the Rcsinx to be horizontal, only diagonal :/
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scoobiedoobiedoo
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(Original post by FaccoyKazz)
hello, thanks so much for working through this publicly i was so stuck! would you be able to explain to me your horizontal forces because i couldn’t get the Rcsinx to be horizontal, only diagonal :/
Oh my I did this question such a long time ago aha but if you are really stuck on forces and static rigid bodies I suggest for you to look at the website maths genie a level revision.

He does revision videos for all topics as well as questions for you to work on with solutions.

Maths takes a lot of practise and time aha
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FaccoyKazz
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(Original post by scoobiedoobiedoo)
Oh my I did this question such a long time ago aha but if you are really stuck on forces and static rigid bodies I suggest for you to look at the website maths genie a level revision.

He does revision videos for all topics as well as questions for you to work on with solutions.

Maths takes a lot of practise and time aha
no worries i understand it was a long time ago!😂thanks so much for the suggestion i definitely will have a look!
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POP977NOW
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drfrost has very good questions
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