A particle moves along a horizontal circle with constant speed. If 'a' is its acceleration and 'E' is its kinetic energyA) a is constant B) E is constant C) a is variable D) E is variable

Speed (u) is constant.: E = 1/2 m u2 = constantAgain 'a' is always directed towards the centre of the circular path. As the particle changes its position ,direction of 'a' also changes. Therefore Option-(4) is correct.