Question

The given graph shows the force applied on an object from $x=0$ to $x=9$.
How much work is done on the object from $x=0$ to $x=9$? Quantities are given in standard units.

• A. $-13.5J$
• B. $-4.5J$
• C. $0J$
• D. $4.5J$
• E. $13.5J$

Answer 1

The correct option is B $-4.5J$

work done $=F.dx$

also the area under F x curve

therefore work done = area under F x curve

work done from x=o to x=3 is positive

area of triangle = $W_1=\frac{1}{2}\times 3\times 3=4.5J$

work done from x=3 to x=6 is negative

$W_2=-\frac{1}{2}\times 3\times 3=-4.5J$

work done from x=6 to x=9

$W_3=-d\frac{1}{2}\times 3\times 3=-4.5J$

hence total work done =$W=W_1+W_2+W_3$

$W=+4.5J-4.5J-4.5J=-4.5J$