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Measure of two quantities along with the precision of respective measuring instrument is $A = 2.5ms^{-1} \pm 0.5ms^{-1}$, $B = 0.10s \pm 0.01s$. The value of AB will be
Explanation
By applying the Rule of significant figure in multiplication and addition. As given that, $A = 2.5ms^{-1} \pm 0.5ms^{-1}$, $B = 0.10s \pm 0.01s$ $x = AB = (2.5)(0.10) = 0.25m$ (consider only significant figure value) $\Delta x/x = \Delta A/A + \Delta B/B = 0.5/2.5 + 0.01/0.10 = (0.05 + 0.025)/0.25 = 0.075/0.25$ $\Delta x = 0.075 = 0.08m$ (rounding off to two significant figures.) $AB = (0.25 \pm 0.08)m$