# Thread: Finding the x and y components

1. Hi. I really need help for this problem:

Four forces act concurrently at one point. Force A has a magnitude of 70 lb and is directed 30 degrees North of East; force B has a magnitude of 60 lb and is directed westward; force C has a magnitude of 50 lb and directed southward; and force D has a magnitude of 40 lb and direction 20 degrees measured in the sense from the negative y-axis toward the positive x-axis. What are the x and y components of the resultant of the four forces?

It was given as a quiz during our summer classes and I failed to answer it. My x-component was 64.30 and my y-component was -2.59. However the correct answers were 14.30 for the x-component and -52.59 for the y-component.

2.

3. Show us how you got 64.30 and -2.59.

4. Originally Posted by nerdhere
Hi. I really need help for this problem:

Four forces act concurrently at one point. Force A has a magnitude of 70 lb and is directed 30 degrees North of East; force B has a magnitude of 60 lb and is directed westward; force C has a magnitude of 50 lb and directed southward; and force D has a magnitude of 40 lb and direction 20 degrees measured in the sense from the negative y-axis toward the positive x-axis. What are the x and y components of the resultant of the four forces?

It was given as a quiz during our summer classes and I failed to answer it. My x-component was 64.30 and my y-component was -2.59. However the correct answers were 14.30 for the x-component and -52.59 for the y-component.

You know that

You also know that , ........

Anyway, what I did first was a graph on how the forces actually looked like. Then I set out table of values.

*Table of Values*

Force -> x-component -> y-component
A 70cos30 70sin30
B -60cos0 60sin0
C 50cos0 -50sin0
D 40sin20 -40cos20

Therefore, the summation of x is 64.30 and y is -2.59.

Actually, I have an illustration of the graph, however uploading failed. So I guess the table will be a great help. Thanks.

6. Originally Posted by xyzt
Originally Posted by nerdhere
Hi. I really need help for this problem:

Four forces act concurrently at one point. Force A has a magnitude of 70 lb and is directed 30 degrees North of East; force B has a magnitude of 60 lb and is directed westward; force C has a magnitude of 50 lb and directed southward; and force D has a magnitude of 40 lb and direction 20 degrees measured in the sense from the negative y-axis toward the positive x-axis. What are the x and y components of the resultant of the four forces?

It was given as a quiz during our summer classes and I failed to answer it. My x-component was 64.30 and my y-component was -2.59. However the correct answers were 14.30 for the x-component and -52.59 for the y-component.

You know that

You also know that , ........

Yup, I know what you're talking about. In our quiz, everything I did was correct except for the table of values.

*Table of Values*

Force -> x-component -> y-component
A 70cos30 70sin30
B -60cos0 60sin0
C 50cos0 -50sin0
D 40sin20 -40cos20

Therefore, the summation of x is 64.30 and y is -2.59.

I really thought I was on the right track because I just followed what I've learned from class. Then when the answers came out, I was in total shock because I couldn't find the error/s in my table. So can you please help me? Thank you.

7. Originally Posted by Harold14370
Show us how you got 64.30 and -2.59.

Anyway, what I did first was a graph on how the forces actually looked like. Then I set out table of values.

*Table of Values*

Force -> x-component -> y-component
A 70cos30 70sin30
B -60cos0 60sin0
C 50cos0 -50sin0
D 40sin20 -40cos20

Therefore, the summation of x is 64.30 and y is -2.59.

Actually, I have an illustration of the graph, however uploading failed. So I guess the table will be a great help. Thanks.

8. Originally Posted by nerdhere
Originally Posted by xyzt
Originally Posted by nerdhere
Hi. I really need help for this problem:

Four forces act concurrently at one point. Force A has a magnitude of 70 lb and is directed 30 degrees North of East; force B has a magnitude of 60 lb and is directed westward; force C has a magnitude of 50 lb and directed southward; and force D has a magnitude of 40 lb and direction 20 degrees measured in the sense from the negative y-axis toward the positive x-axis. What are the x and y components of the resultant of the four forces?

It was given as a quiz during our summer classes and I failed to answer it. My x-component was 64.30 and my y-component was -2.59. However the correct answers were 14.30 for the x-component and -52.59 for the y-component.

You know that

You also know that , ........

Yup, I know what you're talking about. In our quiz, everything I did was correct except for the table of values.

*Table of Values*

Force -> x-component -> y-component
A 70cos30 70sin30
B -60cos0 60sin0
C 50cos0 -50sin0
D 40sin20 -40cos20

Therefore, the summation of x is 64.30 and y is -2.59.

I really thought I was on the right track because I just followed what I've learned from class. Then when the answers came out, I was in total shock because I couldn't find the error/s in my table. So can you please help me? Thank you.

You did things right except you made a fatal error for Force C components: force C has a magnitude of 50 lb and directed southward;

When you put this into the summation, you get the correct results. You are off by 50 in the x direction (and by -50 in the y direction). I feel bad for you.

9. As xyzt pointed out, C is wrong. South (in this notatation) is -90°.

10. Originally Posted by nerdhere
Originally Posted by xyzt
Originally Posted by nerdhere
Hi. I really need help for this problem:

Four forces act concurrently at one point. Force A has a magnitude of 70 lb and is directed 30 degrees North of East; force B has a magnitude of 60 lb and is directed westward; force C has a magnitude of 50 lb and directed southward; and force D has a magnitude of 40 lb and direction 20 degrees measured in the sense from the negative y-axis toward the positive x-axis. What are the x and y components of the resultant of the four forces?

It was given as a quiz during our summer classes and I failed to answer it. My x-component was 64.30 and my y-component was -2.59. However the correct answers were 14.30 for the x-component and -52.59 for the y-component.

You know that

You also know that , ........

Yup, I know what you're talking about. In our quiz, everything I did was correct except for the table of values.

*Table of Values*

Force -> x-component -> y-component
A 70cos30 70sin30
B -60cos0 60sin0
C 50cos0 -50sin0
D 40sin20 -40cos20

Therefore, the summation of x is 64.30 and y is -2.59.

I really thought I was on the right track because I just followed what I've learned from class. Then when the answers came out, I was in total shock because I couldn't find the error/s in my table. So can you please help me? Thank you.
BTW, you are welcome!

11. Originally Posted by xyzt
Originally Posted by nerdhere
Originally Posted by xyzt
Originally Posted by nerdhere
Hi. I really need help for this problem:

Four forces act concurrently at one point. Force A has a magnitude of 70 lb and is directed 30 degrees North of East; force B has a magnitude of 60 lb and is directed westward; force C has a magnitude of 50 lb and directed southward; and force D has a magnitude of 40 lb and direction 20 degrees measured in the sense from the negative y-axis toward the positive x-axis. What are the x and y components of the resultant of the four forces?

It was given as a quiz during our summer classes and I failed to answer it. My x-component was 64.30 and my y-component was -2.59. However the correct answers were 14.30 for the x-component and -52.59 for the y-component.

You know that

You also know that , ........

Yup, I know what you're talking about. In our quiz, everything I did was correct except for the table of values.

*Table of Values*

Force -> x-component -> y-component
A 70cos30 70sin30
B -60cos0 60sin0
C 50cos0 -50sin0
D 40sin20 -40cos20

Therefore, the summation of x is 64.30 and y is -2.59.

I really thought I was on the right track because I just followed what I've learned from class. Then when the answers came out, I was in total shock because I couldn't find the error/s in my table. So can you please help me? Thank you.

You did things right except you made a fatal error for Force C components: force C has a magnitude of 50 lb and directed southward;

When you put this into the summation, you get the correct results. You are off by 50 in the x direction (and by -50 in the y direction). I feel bad for you.
Goodness! Thank you very much! I really am careless. I forgot that C is directed southward. I should have reviewed my answers before handling the paper. Yikes! Thank you again.

12. Originally Posted by mathman
As xyzt pointed out, C is wrong. South (in this notatation) is -90°.
Thank you for your time! I really overlooked C.

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