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08:30
```**Question:**

Displacement time equation of two particles moving along $x$-axis are:

$$\begin{align}
x_1&=(8+3\sin\pi t)\mathrm{m}\\
x_2&=(4\cos\pi t)\mathrm{m}
\end{align}$$

The two particles are at minimum distance after time (in seconds):

(a) $1$
(b) $2$
(c) $3$
(d) All of the above

**Answer:** (b) $2~\mathrm{s}$

**Author's approach:**

At time $t=0$, $x_1$ is at $+8~\mathrm{m}$ and moving towards the positive $x$ axis and $x_2$ is at $+4~\mathrm{m}$ and is moving towards negative $x$ axis. At this time they are at the shortest distance (I disagree with this conclusion). Next ti
`**Question:**

Displacement time equation of two particles moving along $x$-axis are:

$$\begin{align}
x_1&=(8+3\sin\pi t)\mathrm{m}\\
x_2&=(4\cos\pi t)\mathrm{m}
\end{align}$$

The two particles are at minimum distance after time (in seconds):

(a) $1$
(b) $2$
(c) $3$
(d) All of the above

**Answer:** (b) $2~\mathrm{s}$

**Author's approach:**

At time $t=0$, $x_1$ is at $+8~\mathrm{m}$ and moving towards the positive $x$ axis and $x_2$ is at $+4~\mathrm{m}$ and is moving towards negative $x$ axis. At this time they are at the shortest distance (I disagree with this conclusion). Next time
From the following:
    **Question:**

Displacement time equation of two particles moving along $x$-axis are:

$$\begin{align}
x_1&=(8+3\sin\pi t)\mathrm{m}\\
x_2&=(4\cos\pi t)\mathrm{m}
\end{align}$$

The two particles are at minimum distance after time (in seconds):

(a) $1$
(b) $2$
(c) $3$
(d) All of the above

**Answer:** (b) $2~\mathrm{s}$

**Author's approach:**

At time $t=0$, $x_1$ is at $+8~\mathrm{m}$ and moving towards the positive $x$ axis and $x_2$ is at $+4~\mathrm{m}$ and is moving towards negative $x$ axis. At this time they are at the shortest distance (I disagree with this conclusion). Next t
 
3 hours later…
11:45
@JohnRennie: Did I explain my doubt properly sir?
Sorry, I'm busy for a moment ...
No problem sir. I was wondering whether my explanation gave a clear picture of my doubt.
@JohnRennie Are you free now? Or shall we continue afterwards?

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