A force F = x 2 y 2 i + x 2 y 2 j (N) acts on a particle which moves in the XY plane.
(a) Determine F is conservative or not and 
(b) Find the work done by F as it moves the particle from A to C (fig.) along each of the paths ABC, ADC, and AC.

Dear student,

(a)If F is conservative then
Fx=-δUδx,Fy=-δUδySo δFxδy=-δ2Uδyδx=-δ2Uδxδy=δFyδxBut for the given force,δFxδy=2x2y,δFyδx=2xy2Hence the given force is not conservative.
(b)The work done by the given force is 
W=F.ds =(x2y2i+x2y2j).dx i+dy jW=x2y2 dx+x2y2 dy

Along AB, y=0 so WAB =0,
Along BC,dx =0 so WBC=0aa2y2dy =a53j
Thus work done is WABC=WAB+WBC=a53
Along AD,x=0, WAD =0
Along DC,dy=0
WDC=0ax2a2dx=a53Thus WADC =a53j
Along AC,x=y,dx=dy
WAC=20ax4dx=2a53j

​Regards.
 

  • 99
What are you looking for?