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# Mechanics M1 question!

Maths and statistics discussion, revision, exam and homework help.

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1. Mechanics M1 question!
I understand part i. It's part ii that's really annoying me

They're asking for the contact force, which isn't the same as the normal contact force, any idea what I do?
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2. Re: Mechanics M1 question!
This looks kind of confusing, which paper is this?
3. Re: Mechanics M1 question!
(Original post by Namige)
This looks kind of confusing, which paper is this?
OCR January 2011 (Not MEI)

I've never seen anything like it before hahahha
4. Re: Mechanics M1 question!
(Original post by Super Mario 64)
I understand part i. It's part ii that's really annoying me

They're asking for the contact force, which isn't the same as the normal contact force, any idea what I do?
(Original post by Namige)
This looks kind of confusing, which paper is this?
Remember, friction is also a contact force.

We know the normal reaction and friction, find the resultant of them by using Pythagoras theorem. Then find the angle.
5. Re: Mechanics M1 question!
If you find out please tell me, I have M1 in a weeks time so hoping to do well obviously
6. Re: Mechanics M1 question!
(Original post by Namige)
If you find out please tell me, I have M1 in a weeks time so hoping to do well obviously
Did you read my previous post?
It explains how to do it.
7. Re: Mechanics M1 question!
Ah thank you that makes some sense now. How do you find out the angle though? The mark scheme says use tangent to work out adjacent over opposite but isn't tangent opposite over adjacent?...
8. Re: Mechanics M1 question!
(Original post by Super Mario 64)
Ah thank you that makes some sense now. How do you find out the angle though? The mark scheme says use tangent to work out adjacent over opposite but isn't tangent opposite over adjacent?...

R = Normal reaction and Fr = Friction
9. Re: Mechanics M1 question!
(Original post by raheem94)

R = Normal reaction and Fr = Friction
Ah thank you, what's the reason for this though? How come you take it away from 180?
10. Re: Mechanics M1 question!
(Original post by Super Mario 64)
Ah thank you, what's the reason for this though? How come you take it away from 180?
Have you drawn a diagram?

From the diagram you can see the tan inverse gives the angle with the , to find the angle with , you need to subtract from 180.
11. Re: Mechanics M1 question!
(Original post by raheem94)
Have you drawn a diagram?

From the diagram you can see the tan inverse gives the angle with the , to find the angle with , you need to subtract from 180.
I've drawn the diagram
Ah I see you, what do the arrows represent?
12. Re: Mechanics M1 question!
(Original post by Super Mario 64)
I've drawn the diagram
Ah I see you, what do the arrows represent?
See the below diagram:

Taking the tan inverse gives gives the green angle.

We need the angle the resultant makes with the upward slope, so we need to subtract the green angle from 180.

The arrows represented the upward and downward direction of the slope.
13. Re: Mechanics M1 question!
(Original post by raheem94)
See the below diagram:

Taking the tan inverse gives gives the green angle.

We need the angle the resultant makes with the upward slope, so we need to subtract the green angle from 180.

The arrows represented the upward and downward direction of the slope.
Thank you so much this makes complete sense to me now!

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Last updated: May 22, 2012
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