# Incline planes

#1
Idk how they resolved horizontally, where did Nsin35 come from?

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1 year ago
#2
Look at the"triangle" where the ladder is resting on the drum at P. The horizontal component is Nsin(35)
Last edited by mqb2766; 1 year ago
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#3
(Original post by mqb2766)
Look at the"triangle" where the ladder is resting on the drum at P. The horizontal component is Nsin(35)
But how? That isn’t horizontal
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1 year ago
#4
(Original post by r7kytt)
But how? That isn’t horizontal
Resolve N.
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#5
(Original post by mqb2766)
Resolve N.
Resolving for N, you take F from the ground and then the resultant forces, but Nsin35 isn’t the horizontal component...
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1 year ago
#6
(Original post by r7kytt)
Resolving for N, you take F from the ground and then the resultant forces, but Nsin35 isn’t the horizontal component...
? F has nothing to do with resolving N.
N has a horizontal component so draw a right angled triangle (one vertex is P) to resolve things as usual. They've already given you an angle and two of the sides.
Last edited by mqb2766; 1 year ago
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#7
(Original post by mqb2766)
? F has nothing g to do with resolving N.
N has a horizontal component draw a right angled triangle (one vertex is P) to resolve things. They've already given you an angle and two of the sides.
Why does it say F =

Then?
0
1 year ago
#8
(Original post by r7kytt)
Why does it say F =

Then?
Because the (two) forces are in equilibrium (horizontally).
Last edited by mqb2766; 1 year ago
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#9
(Original post by mqb2766)
Because the (two) forces are in equilibrium (horizontally).
Sorry, I still can’t see it. I was under the impression that resolving horizontally had to go in the opposite direction and vice versa to vertically. I’m very confused, I see what you mean by Nsin35 right angle triangle but not sure why they would be equal or rather why it’s took as a horizontal component
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#10
I think the confusion is in the diagram, I think I get it now but the diagram is at an angle. Thank you
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#11
As in, it’s meant to be north not north east
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1 year ago
#12
(Original post by r7kytt)
Sorry, I still can’t see it. I was under the impression that resolving horizontally had to go in the opposite direction and vice versa to vertically. I’m very confused, I see what you mean by Nsin35 right angle triangle but not sure why they would be equal or rather why it’s took as a horizontal component
Why not draw your own diagram, concentrating on the horizontal forces and upload it together with the force equation that describes horizontal equilibrium. It's easier to help if I can understand what you think.
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#13
(Original post by mqb2766)
Why not draw your own diagram, concentrating on the horizontal forces and upload it together with the force equation that describes horizontal equilibrium. It's easier to help if I can understand what you think.
I get it now, the confusion was the diagram. It’s north, not north east. It looked north east, I think I’m just tired
1
1 year ago
#14
(Original post by r7kytt)
I get it now, the confusion was the diagram. It’s north, not north east. It looked north east, I think I’m just tired
What's north? The normal reaction N at P is normal to the ladder and the ladder is inclined at an angle to the horizontal, so N certainly isn't pointing north. The diagram looks OK to me
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#15
(Original post by davros)
What's north? The normal reaction N at P is normal to the ladder and the ladder is inclined at an angle to the horizontal, so N certainly isn't pointing north. The diagram looks OK to me
What??! So why would it be Nsin35???
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1 year ago
#16
(Original post by r7kytt)
What??! So why would it be Nsin35???
N is the normal reaction. Sin(35), see all the earlier posts.
Last edited by mqb2766; 1 year ago
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1 year ago
#17
(Original post by r7kytt)
What??! So why would it be Nsin35???
You're resolving horizontally at this point. The force F is along the ground as per the diagram. The reaction force R is purely vertical as per the diagram so it doesn't contribute. So you're looking at a horizontal force to balance F for equilibrium. It can't be the weight because weight is purely vertical. So we need the component of N in the horizontal direction.

It might help to draw a horizontal line through P so that you can see what the angles are. Since the ladder is at an angle 35 degrees to the ground, a horizontal line through P makes an angle 35 degrees with the ladder (alternate angles). Given that the force N is normal to the ladder at contact point P, you should now be able to resolve N into its horizontal and vertical components.
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#18
But Nsin35 is not horizontal? That’s at a slant??????????

Both forces are horizontal so you can equal them, so why isn’t Nsin35 horizontal but it equals force on the ground ?
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1 year ago
#19
(Original post by r7kytt)
But Nsin35 is not horizontal? That’s at a slant??????????

Not quite sure what you're doing there. N is perpendicular to the plane so slopes approx north-west as per the diagram. The vertical component of N is Ncos35 which you have labelled correctly. The horizontal component of N is Nsin35 pointing to the left (west). You have written Nsin35 in the direction N is pointing in???
0
#20
I see it now thank you!

You confused me because I got it last night, it’s because I drew the triangle wrong lmao
0
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