Since the velocity is tangent to the path, the rate of change of the
speed is the tangential acceleration.
at = dv/dt = 2 + 1.5t ft/s2
The tangential acceleration can be integrated to obtain an equation for the speed as a function of time. Since the plane enters the turn traveling at 176 ft/s, this becomes the lower limit of integration for the velocity,
v = ds/dt = 0.75 t2 + 2 t +
Substituting the time required for the plane to complete the turn, the speed at B becomes
vB = 0.75 (16)2 + 2 (16) + 176
= 400.0 ft/s