A toy train has a track with a radius of 1 π‘š. The train is at rest at time 𝑑 = 0, when the train is given a tangential acceleration of 0.25 π‘š 𝑠 2 ⁄ . What is the magnitude of the train’s acceleration

after 2 𝑠 (in π‘š 𝑠 2 ⁄ )? the answer was 0.25sqrt2 and I do not understand. please help! Thanks!