What am I doing wrong in my calculations

In summary, the problem involves three masses (m1 = 3.3 kg, m2 = 9.9 kg, and m3 = 6.6 kg) hanging from three identical springs in a motionless elevator with a spring constant of 229.57 N/m. The elevator then moves downward with a velocity of v = -2.3 m/s but accelerates upward with an acceleration of a = 4.8 m/s2, resulting in the top spring being extended from its unstretched length by 20.987 cm. The tension in the top spring is not explicitly stated, but can be determined by starting with the free body diagram of the bottom mass and working up.
  • #1
aruji73
19
0
What is the distance the upper spring is extended from its unstretched length?
Now, three masses m1 = 3.3 kg, m2 = 9.9 kg and m3 = 6.6 kg hang from three identical springs in a motionless elevator. The springs all have the same spring constant of 229.57N/m

Now the elevator is moving downward with a velocity of v = -2.3 m/s but accelerating upward with an acceleration of a = 4.8 m/s2. (Note: an upward acceleration when the elevator is moving down means the elevator is slowing down.)

What is the distance the upper spring is extended from its unstretched length?
cm


I did

(3.3(9.8+4.8))/229.57=0.20987 m =20.987 cm
 
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  • #2
aruji73 said:
What is the distance the upper spring is extended from its unstretched length?
Now, three masses m1 = 3.3 kg, m2 = 9.9 kg and m3 = 6.6 kg hang from three identical springs in a motionless elevator. The springs all have the same spring constant of 229.57N/m

Now the elevator is moving downward with a velocity of v = -2.3 m/s but accelerating upward with an acceleration of a = 4.8 m/s2. (Note: an upward acceleration when the elevator is moving down means the elevator is slowing down.)

What is the distance the upper spring is extended from its unstretched length?
cm

I did

(3.3(9.8+4.8))/229.57=0.20987 m =20.987 cm
That looks good to me.

Is there a problem regarding significant digits?
 
  • #3
Hi I am not sure my answer is supposed to be in cm but I am sure I have done it right puzzling indeed
 
  • #4
In your problem you have mensioned three springs and three masses. Whether the springs are connected with each other? If yes, who?
 
  • #5
springs are connected is m1 at top is connected to m2 in middle which is connected to m3 in the bottom
 
  • #6
So, the spring at the top is supporting, directly or indirectly, all three masses? Won't that increase the tension in it?
 
  • #7
this is the pic
 

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  • #8
Right, so what is the tension in the top spring? If you're not sure, start with the free body diagram of the bottom mass and work up.
 

Related to What am I doing wrong in my calculations

1. Why are my calculations not matching the expected results?

There could be several reasons for this. It is possible that there is an error in your formula or equation. Double check to make sure you have input all the correct values and used the correct mathematical operations. It is also possible that there is an error in your data or measurements. Make sure you are using accurate and precise data. Additionally, check your units to ensure they are consistent throughout your calculations.

2. How can I avoid making mistakes in my calculations?

One way to avoid making mistakes in your calculations is to double check your work. This means going back and carefully reviewing each step of your calculations, as well as checking for any typos or errors. Another helpful tip is to break down complex calculations into smaller, more manageable steps. This can help prevent mistakes and make it easier to catch any errors.

3. What should I do if I am getting different results each time I do my calculations?

If you are getting different results each time you do your calculations, it is likely that there is a mistake somewhere in your process. Make sure you are using the same data and formula each time, and check for any inconsistencies or errors. It can also be helpful to have someone else check your work to catch any mistakes you may have overlooked.

4. How do I know if my calculations are accurate?

The best way to determine the accuracy of your calculations is to compare your results to a known or expected value. This could be a value from a previous experiment or a value obtained from a reliable source. If your results are consistent with the expected value, then your calculations are likely accurate. Additionally, you can use statistical methods to determine the precision and accuracy of your data.

5. What can I do if my calculations are not giving me the desired outcome?

If your calculations are not giving you the desired outcome, it may be helpful to revisit your assumptions and data. Make sure you have all the necessary information and that your data is accurate. It may also be useful to consult with a colleague or mentor for their input and to brainstorm potential solutions. Finally, don't be afraid to try different approaches or methods in your calculations to see if that yields the desired outcome.

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