Physics 9702 · AS & A Level · Errors and uncertainties

Errors and uncertainties — practice question

(a)[1]

A cylinder has diameter $d = 0.0125\,\text{m} \pm 1.6\%$. Find the absolute uncertainty for this measurement.

(b(i))[1]

The cylinder in (a) is resting on a horizontal surface. The pressure $p$ applied to the surface by the cylinder is given by $p = \dfrac{4W}{\pi d^2}$. The cylinder’s measured weight $W$ is $0.38\,\text{N} \pm 2.8\%$. Determine $p$.

(b(ii))[2]

Find the absolute uncertainty in $p$.

Worked solution & mark scheme

This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: Absolute uncertainty found from $(1.6/100) \times 0.0125 = 2 \times 10^{-4}\,\text{m}$

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