Two particles $A$ and $B$ move anticlockwise with the same speed $v$ in a circle of radius $R$ and are diametrically opposite to each other. At $t=0$, $A$ is given a constant acceleration (tangential) $a_t = \frac{72v^2}{25\pi R}$. Calculate the time in which $A$ collides with $B$, the angle traced by $A$, its angular velocity and radial acceleration at the time of collision.

In the first part of question I thought to equate the time for both particles when they collide. But I am not able to find the time taken by the first particle $A$ .

Please help me in this.

What would it mean for the particles to collide? The final times would be the same. True. But would anything else be equal besides the time?