1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution Since the tangent moves at uniform angular speed ,the particle also moves with constant angular speed . Is it correct ? If it is right then the particle has only radial acceleration given by ##ω^2r## ,where 'r' is the radius of curvature . r = sec2x r ( x= πa/4) = 1/√2 . Hence resultant acceleration at x= πa/4 = 2√2 . I don't have the answer key . Have I interpreted the question correctly and done it right ? I would be grateful if somebody could verify my work .