A slightly more complicated arrangement occurs if the track is raised at the end opposite the pulley to make an angle of about 2 degrees with the horizontal. The block of wood flat on the table should be enough here. With the 20-g mass still hanging from the end of the string the net force on the system of the cart and hanging mass consists of more than one force. Note: the assumption that frictional effects are little changed by raising the ramp to a small angle should be a very good one. Again address the same question: does the total cgange in kinetic energy equal the change in the potential energy of the system? Collect appropriate data to determine the validity of this hypothesis. Keep in mind that the cart will be changing height as it moves along the ramp now - but not by the same amount that the hanging mass changes height