b
જંતુ સ્થિર હોય ત્યારે \(\,N cos\,\theta \,\, = \,\,mg\,\,;\,\,N sin\,\theta \,\, = \,\,ma\)

\(\therefore \,\tan \theta  = \frac{a}{g}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,........(\,\,\,1)\)

પરંતુ \({\text{y  =  k}}{{\text{x}}^{\text{2}}}{\text{ }}\,\,\,\therefore \frac{{dy}}{{dx}} = 2kx = \) ઢાળ \(\,( = \,\,tan\,\,\theta )\,\,\,\)

\(\therefore \,2kx = \frac{a}{g}\,\,\,\therefore \,\,\,\,x = \frac{a}{{2gk}}\)