An engineer wishes to determine the spring constant of a helical spring. She fir
ID: 2256694 • Letter: A
Question
An engineer wishes to determine the spring constant of a helical spring. She first puts enough weights on the spring to pull the coils apart. Using a simple wooden meter stick with millimeter marks, she finds that the elevation of the end of the spring changes from 63.5 cm to 52.6 cm when she adds a lab weight whose stamped value is 400 grams. The uncertainty of the stamped weight is 2%. Take g = 9.81 m/s2 with negligible uncertainty.
a. What is the best estimate of the spring constant? (in N/cm)?
b. What is the uncertainty in the value of the spring constant? (in N/cm)
Explanation / Answer
1) end of spring change = 63.5 - 52.6 = 10.9cm
2) W = mg = 400g * 9.8 m/s2 = 3920N
3) Vision error.
Didn't keep the eyes and the wooden meter stick on the horizontal line.
4) Does question 4 and 2 are repetitive ?
Anyway, W = mg = 400g * 9.8 m/s2 = 3920N
5) Uncertainty of the weight adds on the spring could due to
Different environment
Different observers
Different materials of the weight being made
6) A ccording to Hooke's law,
F = k X
3920N = 10.9cm *k
k = 359.6 N/cm
7) Measurement values from the previous experiments,