1. Oct 17, 2013

### MGCLO

here is the problem image

http://tinypic.com/r/qxrqdu/5

Weight A is connected via a string to Weight B. Weight B is connected to a string to Weight C. Mass of A is 21 KG. Mass of B is 5 KG. Mass of C is 10 KG. the kinetic friction between the table and the 5 KG weight is 0.22

i got 2.75 M/S^2 for acceleration is that correct?

i need to know whats the tension in the string between A and B. include steps plz

2. Oct 17, 2013

### turbo

Can you show and explain your work? There are lots of talented people here, but they are not allowed to do your homework for you.

3. Oct 17, 2013

### MGCLO

well whats the point of this website?

4. Oct 17, 2013

### MGCLO

I figured out the acceleration part but I cant figure out the Tension!

5. Oct 17, 2013

### Staff: Mentor

To get the tension in the string between A and B, draw a free body diagram on A, and write down the Newton's 2nd Law force balance on A.

6. Oct 17, 2013

### Ibix

As per the rules you agreed to when you created your account, you need to show your working so far before we will help.

7. Oct 17, 2013

### MGCLO

well since we don't have an angle. then 210-ft= 2.75(5)
so 210-ft= 13.75

-ft = 13.75-210
ft= 196.25 ?
is that correct!

8. Oct 17, 2013

### Staff: Mentor

No. If you are doing a force balance on weight A, shouldn't the 5kg on the right hand side of your equation be 21kg?

9. Oct 17, 2013

### MGCLO

correct my bad got confused. using different weights in one problem does not make sense either.

so 210-ft= 2.75(210)

I got ft= 367.5 ?

10. Oct 17, 2013

### Staff: Mentor

You need to show your work on the problem before you may receive tutorial help here on the PF. Please check your PMs.

11. Oct 17, 2013

### Staff: Mentor

The point of this website is to help you learn how to learn. If we just spoon-feed you the answers, that will no help you to improve in your understanding of the subject, and will not help you to be able to figure out problems on your own (which is how real life works).

12. Oct 17, 2013

### MGCLO

ok I showed my work for that part. can anyone tell me if 367.5 is correct?

13. Oct 17, 2013

### Staff: Mentor

No. It's not 2.75(210), it's 2.75(21). Also, you did the algebra wrong. You have the right idea, but you gotta be more careful with the math.

Chet

14. Oct 17, 2013

### MGCLO

210-ft=57.75

ft=152.25 ???

15. Oct 17, 2013

### MGCLO

16. Oct 17, 2013

### Staff: Mentor

Yes, provided your solution for the acceleration is correct.

17. Oct 17, 2013

### MGCLO

how about the tension on the cord between A and B
ft=152.25 ???

18. Oct 17, 2013

### Staff: Mentor

That is what you calculated.

19. Oct 17, 2013

### MGCLO

yes.

21KG(10M/S^2) -FT= ma
210-FT=21(2.75)
FT=152.25

20. Oct 17, 2013

### MGCLO

so? is it correct or not!