a cart accelerates from rest along a level track as a result of the action of a fan. (a) Since the cart accelerates then according to Newton’s Second Law there must be a net horizontal force on it. What is the source of that force? Hints: (1)The fan cart unit cannot exert a force on itself, (2) What does Newton’s Third Law tell you?, (3) Would the fan cart unit accelerate if it were in outer space? (b) If friction is negligible identify the three forces acting on the cart and describe the direction of there forces relative the the coordinate system shown when the movie is opened in VideoPoint. (c)find the magnitude and direction of the acceleration of the cart in the horizontal direction. Explain how you determined the acceleration. Is it constant? How do you know? (d) What is the net work done on the cart as it travels from its location in frame 1 to its location in frame 14? What agent does this work?