Q125 / 155 · WBJEE 2016 · Physics
If $x=a t+b t^{2},$ where $x$ is in metre $(\mathrm{m})$ and $t$ is in hour $(\mathrm{h})$, then unit of $b$ will be
- A$\frac{\mathrm{m}^{2}}{\mathrm{h}}$
- B$m$
- C$\frac{m}{h}$
- Correct answerD$\frac{m}{h^{2}}$
Solution
Given, $x=a t+b t^{2}$
$\begin{array}{l}
{[x]=\left[b t^{2}\right]} \\
\text { Unit of } b=\frac{x}{t^{2}}=\frac{\text { metre }}{(h)^{2}}=\frac{m}{h^{2}}
\end{array}$
Hence, the correct answer is option: 'D'.