The cart travels the track again and now experiences a constant tangential acceleration from point A to point C. The speeds of the cart are 12.4 ft/s at point A and 19.4 ft/s at point C. The cart takes 4.00 s to go from point A to point C, and the cart takes 1.50 s to go from point B to point C.
What is the cart's speed at point B?