Register to reply

Hooke's Law Lab and theoretical y-value! Really need some help!

by exparrot
Tags: hooke, theoretical, yvalue
Share this thread:
exparrot
#1
Nov12-09, 07:34 PM
P: 21
I did a Hooke's Law lab in class last week and one of the post-experiment questions asks to explain why the graph made should be a straight line and what should the slope and y-intercept be in terms of quantities in this lab? I know that Hooke's Law demonstrates that the amount a spring is stretched (displaced) is directly proportional to the restoring force, thus the line of the graph would be linear. For my graph, I have the length of the spring in meters (x-axis) vs. the F (m*g) in newtons. The slope would be the k constant and the y-intercept, I assume, would be 0 as if you have 0 displacement, the resultant restoring force would be 0. Okay so I answer that just fine and move on to question 2. Question 2 asks me find the percent difference between the experimentally obtained y-intercept and the theoretical value obtained in question 1. My experimentally obtained y-intercept is 0.0014, and if I assumed correctly in the previous question, my theoretical y-intercept is 0. How would I go about finding the percent difference? I would have 0 in the denominator and I wouldn't get a percent difference, although there is clearly a small difference. Is my theoretical value for the y-intercept correct? I would really appreciate the help! Thanks!
Phys.Org News Partner Science news on Phys.org
'Office life' of bacteria may be their weak spot
Lunar explorers will walk at higher speeds than thought
Philips introduces BlueTouch, PulseRelief control for pain relief
Delphi51
#2
Nov13-09, 03:06 PM
HW Helper
P: 3,394
I have the length of the spring in meters
This suggests that you used not the spring stretch x, but its original length L plus the stretch x. If so, your y-intercept will not be zero.

But most likely, you used the extension x on the horizontal axis and everything you wrote makes sense. If you predict 0 and get 0.0014 the % difference between them does not make much sense, but I would use 100% if I had to have such an answer.


Register to reply

Related Discussions
Hooke's law General Physics 3
Hooke's law Introductory Physics Homework 1
Hooke's Law General Physics 4
Hooke's Law Advanced Physics Homework 6
Hooke's law Introductory Physics Homework 13