Physics 9702 · AS & A Level · Errors and uncertainties

Errors and uncertainties — practice question

The strain energy $W$ stored in a spring depends on its spring constant $k$ and its extension $x$. This spring follows Hooke’s law, and $W$ is found by using the equation below. $W = \frac{1}{2}kx^2$ The spring constant is $100 \pm 2\,\text{N m}^{-1}$ and the extension is $0.050 \pm 0.002\,\text{m}$. What percentage uncertainty is there in the calculated value of $W$?

  • A6%
  • B10%
  • C16%
  • D32%

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