According to definition, a particle performing uniform circular motion must have fixed radius of circular path and it must move with constant speed, so we have given that particle is moving in circular path having fixed radius of r=5m and constant speed v=2ms-1. So, yes, particles are performing uniform circular motion. Acceleration of uniform circular motion is given by a=v2r on putting the values, we get, acceleration of uniform circular motion is a=45=0.8ms-2.