A wheel is rotating about an axis that is in the z-direction. The angular velocity is at , increases linearly with time and is at . We have taken counterclockwise rotation to be positive. Is the angular acceleration during this time interval positive or negative? During what time interval is the speed of the wheel increasing? During what time interval is the speed of the wheel decreasing? What is the angular displacement of the wheel at 7 seconds? Please use all the formulas and show work in step by step processes with detailed information.