Question

Figure here shows the frictional force versus displacement for a particle in motion. The loss of kinetic energy in travelling over $x=0$to$20m$ will be :

• A. $250$ J
• B. $200$ J
• C. $150$ J
• D. $10$ J

Answer 1

Answer: (A)

$250$ J

Loss in kinetic energy is equal to the work done by the frictional force$=\int \overrightarrow{f}.\overrightarrow{dx}$

Thus work done is equal to the area under the given curve. Therefore area is given by,

$=(\frac{1}{2}\times (5+15)\times 5)+(15\times 5)+(\frac{1}{2}\times (15+10\left)\right)\times 10)=250J$