Questions: Axis of rotation

Transcript text: Axis of rotation

Solution

Solution Steps

Step 1: Torque and Force

The ease of opening a door depends on maximizing the torque applied for a given force. Torque is given by τ = rFsinθ, where r is the distance from the axis of rotation, F is the applied force, and θ is the angle between the force and the lever arm.

Step 2: Maximizing Torque

To maximize torque for a given force, we need to maximize r and sinθ. The angle θ is maximized when the force is applied perpendicular to the door (θ = 90 degrees, sinθ = 1).

Step 3: Optimal Door Knob Placement

The distance r is maximized when the doorknob is placed as far from the axis of rotation (hinges) as possible.