Question

For a certain body, the velocity-time graph is shown in the figure. The ratio of applied forces for intervals AB and BC are

• A. $-\frac{1}{3}$
• B. $-\frac{4}{5}$
• C. $\frac{3}{5}$
• D. $-\frac{2}{3}$

Answer 1

The correct option is A $-\frac{1}{3}$

Ratio of applied force = Ratio of acceleration (as $F=ma$)

Acceleration is the slope of v-t curve
Therefore,
$\Rightarrow \frac{a_{AD}}{a_{DC}}=\frac{\tan {30}^{\circ }}{\tan {120}^{\circ }}=\frac{\frac{1}{\sqrt{3}}}{-\sqrt{3}}=\frac{-1}{3}$