A particle moving with uniform retardation along a straight line covers distances $a$ and $b$ in successive…
- $\frac{2(a q-b p)}{pq(p+q)}$
- $\frac{2(b p-a q)}{pq(p+q)}$
- $\frac{2(a q+b p)}{pq(p+q)}$
- $\frac{2(a q-b p)}{pq(p-q)}$
Solution
\(\begin{aligned}
& a=u p-\frac{1}{2} f p^2 \quad \ldots (i) \\
& \text {For } A C, a+b=u(p+q)-\frac{1}{2} f(p+q)^2 \quad \ldots (ii) \\
& \text {(i) and (ii) } \Rightarrow a+b \\
& =\frac{\left(a+\frac{1}{2} f p^2\right)}{p}(p+q)-\frac{1}{2} f(p+q)^2 \\
& \frac{a+b}{p+q}=\frac{a}{p}+\frac{1}{2} f p-\frac{1}{2} f p-\frac{1}{2} f q, \\
& \frac{1}{2} f q=\frac{a}{p}-\frac{a+b}{p+q} \quad=\frac{a p+a q-a p-b p}{p(p+q)} \\
& \frac{1}{2} f q=\frac{a q-b p}{(p+q)}, \quad f=\frac{2(a q-b p)}{\mathrm{p} q(p+q)}
\end{aligned}\)Asked in: JEE Mains - Motion In One Dimension - Test 2