A professor's office door is 0.90 wide, 2.0 high, and 4.0 thick; has a mass of 25 ; 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 at rest, the door closer exerts a torque of 5.0 . What is the least force that you need to apply to the door to hold it open?