Using conservation of energy to find spring constant but off number

AI Thread Summary
The discussion focuses on calculating the spring constant for a metal sphere oscillating on a vertical spring, with initial and final heights provided. The user initially calculates a spring constant of 114 N/m, while suspecting the correct value should be 180 N/m. There is uncertainty regarding the correct interpretation of initial and final heights in the energy conservation equation. The user notes that as the spring stretches, the sphere's gravitational potential energy decreases while its spring potential energy increases. Clarification on the height values and their application in the calculations is sought.
slambert56
Messages
20
Reaction score
0
Okay so I think the answer should be 180N/m unless the book is wrong and I got 114N/m. Now if there is a mistake in my work shown in the picture it would have to be the height final or height initial. I am going with height inital is the x initial and the height final equals the x final.(I think this is correct)

question; a .60kg metal sphere oscillates at the end of a vertical spring. as teh spring stretches from .12 to .23m(relative to its unstrained length) the speed of the sphere decreases from 5.7 to 4.80m/s. what is the spring constant of the spring?
http://img231.imageshack.us/img231/8118/001ql.jpg

Uploaded with ImageShack.us
sorry for the work on the back that you can see. any help would be greatly appreciated!
 
Last edited by a moderator:
Physics news on Phys.org
As the spring stretches, the mass is at a lesser height, therefore has less gravitational potential energy, but more potential energy due to the spring.

You could consider the height to be -x.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Spring Problem Involving Variables and Constants Only
Replies
3
Views
1K
Why can we move the spring with constant speed when we apply a force?
Replies
29
Views
2K
A rocket on a spring, related to potential/kinetic energy
Replies
3
Views
2K
Why doesn't this solution work? (Springs and Conservation of Energy)
Replies
2
Views
1K
Find elastic energy in the compressed spring.
Replies
12
Views
3K
Finding Spring Constant & Energy w/ Doubt in Exercise
Replies
7
Views
2K
Why is my solution to finding the spring constant incorrect?
Replies
3
Views
2K
Vertical spring & maximum length
Replies
6
Views
971
Problem of spring block system: force vs conservation of energy
Replies
20
Views
3K
Spring conservation of energy problem
Replies
14
Views
3K

Hot Threads

Recent Insights

Back
Top