Harmonic Oscillator Homework: Graph, Spring Constant & Weight

AI Thread Summary
The discussion centers on a harmonic oscillator experiment involving a spring and weights, where the period of oscillation was measured for varying weights. The calculated spring constant was found to be approximately 13.2 N/m, with an expected value around 10 N/m. The weight of the basket was estimated to be about 30 grams, although there was confusion regarding the mass calculations. Participants noted that the original poster had initially neglected to square the periods in their calculations. The conversation emphasizes the importance of accurately interpreting the data and applying the correct formulas in harmonic motion problems.
Karol
Messages
1,380
Reaction score
22

Homework Statement


A test was made with a basket and 20 gram weights. they were put in the basket which hang on a spring, the basket was raised and released. the period was measured for a few number of weights in the basket. the results are as follows. the first of every pair is the number of weights and the second is the period in seconds:
(2, 0.53), (3, 0.60), (4, 0.66), (5, 0.72), (6, 0.77)
Draw a graph of T2 as a function of the number of weights, n. comes out a straight line.
What is the spring constant and the weight of the basket.

Homework Equations


Period: $$T=2\pi\sqrt{\frac{m}{c}}$$

The Attempt at a Solution


From the above equation $$T^2=\frac{4\pi^2}{c}\cdot m$$
The slope $$\frac{4\pi^2}{c}$$ based on the last and first couples:
##\frac{4\pi^2}{c}=\frac{0.77-0.53}{(6-2)\cdot 0.02}=3\rightarrow c=13.2##
The spring constant c should be around 10[N/m]
The intersection with the T2 axis: i take the first pair:
##0.53=3\cdot 0.04+B\rightarrow B=0.41##
I insert this B into: $$T^2=\frac{4\pi^2}{c}\cdot m$$
And get:
##0.41=3\cdot m_{basket} \rightarrow m_{basket}=0.14##
It should be around 30 grams
 

Attachments

  • Snap1.jpg
    Snap1.jpg
    6.6 KB · Views: 494
Last edited:
Physics news on Phys.org
Not sure why you did what you did, so:

Your basic period is as you say, T = 2π√(m/k). (Use k instead of c. c is usually associated with damping).

But you realize that the basket has some mass also. So what is m actually?

Can you pick data points to solve for T (and incidentally the basket weight also)?
 
  • Like
Likes 1 person
You forgot to square the periods.
 
dauto said:
You forgot to square the periods.

That part the OP already did.

The second part of the question was "What is the spring constant and the weight of the basket." The provided data was in T, not T2,
 
rude man said:
That part the OP already did.

The second part of the question was "What is the spring constant and the weight of the basket." The provided data was in T, not T2,

No, they didn't. They forgot to do it. Look at their calculation of the slope.
 
dauto said:
No, they didn't. They forgot to do it. Look at their calculation of the slope.

You're right, I saw the graph & thought they got it right. I should have read the part where they said they didn't!

Anyway, my response was to part 2 only.
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Back
Top