Question

An $F-x$ graph is shown below. Find the difference in initial and final potential energies from $x=0\text{m}$ to $x=3\text{m}$.

• A. $5\text{J}$
• B. $10\text{J}$
• C. $15\text{J}$
• D. $20\text{J}$

Answer 1

The correct option is C $15\text{J}$

Change in potential energy is the negative of the work done by the internal conservative force.
$\Delta U=U_f-U_i=-\underset{i}{\overset{f}{\int }}\overrightarrow{F}.\overrightarrow{dr}$
$=$ Area under ($F-x$) curve
$=5\times 3=15\text{J}$