The box of negligible size is sliding down along a curved path defined by the parabola y =...

The box of negligible size is sliding down along a curved path defined by the parabola y = 0.4x2. When it is at A(xA = 2 m, yA = 1.6 m), the speed is v = 8 m/s and the increase in speed is dv/dt = 4 m/s2. Determine the magnitude of the acceleration of the box at this instant.