A professor's office door is 0.98 m wide, 1.87 m high, and 4.09 cm thick; has a mass of 20.65 kg; and pivots on frictionless hinges. A "door closer" is attached to the door and the top of the door frame. When the door is open and is at rest, the door closer exerts a torque of 4.06 M·m. What is the least force that you need to apply to the door to hold it open?