A particle is projected with speed \( u \) from \( O \) along \( y \)-axis. If acceleration of t...

A particle is projected with speed \( u \) from \( O \) along \( y \)-axis.
If acceleration of the particle is \( (a \hat{i}+a \hat{j}) \), then equation of trajectory of the particle is :
(a) \( y=\frac{1}{2} \frac{a x^{2}}{u^{2}} \)
(b) \( (y-x)^{2}=\frac{2 x u^{2}}{a} \)
(c) \( (x-y)^{2}=\frac{2 y u^{2}}{a} \)
(d) \( x^{2}+y^{2}=\frac{2 x u^{2}}{a} \)
\( \mathrm{P} \)