Question

From the following displacement-time graph find out the velocity of a moving body

• A.
• B. 3 m/s
• C.
• D.

Answer 1

The correct option is C

In first instant you will apply $\upsilon =tan\theta$and say,$\upsilon -tan{30}^{\circ }=\frac{1}{\sqrt{3}}m/s.$

But it is wrong because formula $\upsilon =tan\theta$is valid when angle is measured
with time axis.

Here the angle is taken from displacement axis. So angle from time axis
$={90}^{\circ }-{30}^{\circ }-{60}^{\circ }$

Now,$\upsilon -tan{60}^{\circ }=\sqrt{3}$