Question

A $5kg$ block moves in a striaght line on a horizontal frictionless surface under the influence of a force that varies with position as shown in figure. The workdone by this force as the block moves from the origin to $x=8m$.

• A. $35\text{J}$
• B. $25\text{J}$
• C. $20\text{J}$
• D. $30\text{J}$

Answer 1

The correct option is B $25\text{J}$

Work done (w) = area under F-x graph
= Area of part $III$+ Area of part $IV$
+ Area of part $V$
$=2\times 10+\frac{1}{2}\times 2\times 10+\frac{1}{2}\times 2\times (-5)=20+10-5=25\text{J}$