Question

Force versus displacement curve is shown in the diagram. Find the change in kinetic energy by the force at the end of $30\text{m}$.

• A. $25\text{J}$
• B. $50\text{J}$
• C. $75\text{J}$
• D. $100\text{J}$

Answer 1

The correct option is B $50\text{J}$

According to work energy theorem we know that,
Change in kinetic energy $=$ Net work done.

We also know that net work done is
$=$ Area under $F-S$ curve
$=$Area of tringle $OAB$$-$ Area of tringle $BDC$

$=\frac{1}{2}\times 20\times 10-(\frac{1}{2}\times 10\times 10)$
$=50\text{J}$

Hence the change in kinetic energy
$=50\text{J}$

Option B is the correct answer