Question

A body travels uniformly a distance of $\left(13.8\pm0.2\right)m$ in a time$\left(4.0\pm0.3\right)s$. The velocity of the body within error limits is

• A. $\left(3.45\pm0.2\right)m s^{-1}$
• B. $\left(3.45\pm0.3\right)m s^{-1}$
• C. $\left(3.45\pm0.4\right)m s^{-1}$
• D. $\left(3.45\pm0.5\right)m s^{-1}$

Answer 1

Answer: (B)

Here, $S=\left(13.8\pm0.2\right)m$
and $t=\left(4.0\pm0.3\right)s$
Expressing it in percentage error, we have
$S=13.8\pm\frac{0.2}{13.8}\times100\%=13.8\pm1.4\%$
and $t=4.0\pm\frac{0.3}{4}\times100\%=4\pm7.5\%$
$\because v=\frac{S}{t}=\frac{13.8\pm1.4\%}{4\pm7.5\%}=\left(3.45\pm8.9\%\right)$
$=\left(3.45\pm0.03\right)m s$