Figure 6.38: Figure for Problem 6.8 3 Figure 5.38 shows the top view of a revolving door that has a total moment of inertia. for rotations about point 0 of 149.70 kg-m2. The door is initially at rest (no motion or rotation). A person starts pushing on it with a force of 90 N that makes an angle of 15 relative to the perpendicular to the door panel. The person continues to push on the door in this way until it rotates Sir/'4 radians counterclockwise. You may assume that force magnitude and angle relative to the perpendicular do not change as the door rotates. How long [in seconds) will it take until the person stops pushing? r