There are 2 components of acceleration.

Towards center: V2/R = 40 x 40 /400 = 4 m/s2

Tangent( orthogonal to center) = 3 m/s2

Resultant of 1 and 2 above = 5 m/s2

can u explain clearly??i don't understand

As the car is moving along a circular path, it will experience two types of accelerations:1) Tangential accelerationThis is the acceleration that occurs in a straight line, whose value is given to us as 3 m/s22) Centripetal accelerationThis is what causes objects moving in a circular path to be flung outwards. Its value can be calculated from the formula A= v2/r, where v is linear velocity and r is the radius of the path. Putting all values into the formula, we get the value of centripetal acceleration as 4m/s2.Always, tangential or linear acceleration is along a tangent to the path, while centripetal acceleration along the radius vector of the path. So they always lie perpendicular to each other. The net acceleration is given by sqrt(A2+a2), where A and a are linear and centripetal acceleration respectively.Hence we get the value of acceleration as 5 m/s2.