# M1 question help!Watch

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#1
Bill walks 4km due west from O to A and then 5km in a north-east direction from A to B. Find the distance of B from O.
I am getting the answer as 3km but the answer in the book is 3.57km. How could that answer come? Any ideas anyone?
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2 years ago
#2
Assuming that "carries a B" means "carries at B" and there is an upward force at A when it is not zero.

"The answers given come from the eq 50(1.44-x)^2=34.56(1.44-x)+115.2x+50x^2 with the 34.56 term removed for part ii.

I am not sure of the wording of what you have given us (What does "last one" mean?)

I think that for M1 we would have to use that the maximum force at A will occur when the support X is at B in which case the force at A will be 25 (using moments about B). The force at X will be (using Sigma Fy=0 for equilibrium) 40+50-25=65.
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#3
(Original post by nerak99)
Assuming that "carries a B" means "carries at B" and there is an upward force at A when it is not zero.

"The answers given come from the eq 50(1.44-x)^2=34.56(1.44-x)+115.2x+50x^2 with the 34.56 term removed for part ii.

I am not sure of the wording of what you have given us (What does "last one" mean?)

I think that for M1 we would have to use that the maximum force at A will occur when the support X is at B in which case the force at A will be 25 (using moments about B). The force at X will be (using Sigma Fy=0 for equilibrium) 40+50-25=65.
the last one was actually meaning the last sentence, that's it. Thanks for helping me.
0
2 years ago
#4
(Original post by Rashina)
the last one was actually meaning the last sentence, that's it. Thanks for helping me.
Hey! Don't delete a question using edit like that because it makes the answer useless for anyone else. Raise a new question.
0
2 years ago
#5
(Original post by Rashina)
Bill walks 4km due west from O to A and then 5km in a north-east direction from A to B. Find the distance of B from O.
I am getting the answer as 3km but the answer in the book is 3.57km. How could that answer come? Any ideas anyone?
Looking at this as vectors we have

Where the Cos 45 is due to splitting the NE direction into x and y components.
This equals

and Pythagoras gives us 3.5659
0
2 years ago
#6
(Original post by Rashina)
Bill walks 4km due west from O to A and then 5km in a north-east direction from A to B. Find the distance of B from O.
I am getting the answer as 3km but the answer in the book is 3.57km. How could that answer come? Any ideas anyone?
Or use the cosine rule. Your answer suggests that you think that any triangle with sides 4 and 5 must be a 3,4,5 traingle. It depends on the angle between the sides.
0
#7
(Original post by nerak99)
Looking at this as vectors we have

Where the Cos 45 is due to splitting the NE direction into x and y components.
This equals

and Pythagoras gives us 3.5659
How do I find the direction of the displacement OB?
0
2 years ago
#8
Well assuming you want from North, the Vector is 0.4645 West (Cos it is negative), 3.5355 North. If you draw this as a Triangle the angle anticlockwise from North is atan (0.4645/3.5355).

As the other poster said, you could use the Cos rule which may suit the M1 syllabus. To me, this is over complicated but then I am very used to vectors for solving this kind of thing.
0
2 years ago
#9
Desperately need help on this. Can anyone help please?

An object can slide on a path inclined at 15 degrees to the horizontal. It is acted on by a force of magnitude 50 N, acting at an angle of 5 degrees to the upward vertical, as shown in the diagram. Find the components of the force a) in directions parallel to and at right angles to the path b) in horizontal and vertical directions, c) in directions parallel to the path and horizontally, d) in directions at right angles to the path and horizontally, e) in directions parallel to the path and vertically f) in directions at right angles to the path and vertically.
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#10
(Original post by Neil Capelli)
Desperately need help on this. Can anyone help please?

An object can slide on a path inclined at 15 degrees to the horizontal. It is acted on by a force of magnitude 50 N, acting at an angle of 5 degrees to the upward vertical, as shown in the diagram. Find the components of the force a) in directions parallel to and at right angles to the path b) in horizontal and vertical directions, c) in directions parallel to the path and horizontally, d) in directions at right angles to the path and horizontally, e) in directions parallel to the path and vertically f) in directions at right angles to the path and vertically.
You should probably post this in a separate thread made by you in the maths forum so that many people can view it. My question at the top is already answered so there are chances many people could ignore your question.
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