Analyze the example of this door knob wheel and axle.
• The radius of the wheel, or in this case the handle, is 4.125 inches.
• The radius of the axle that opens the latch (inside the mechanism) is 0.125 inch. The actual effort force needed to open the door is 2.25 pounds.
The efficiency of this type of door knob is 85%.
Calculate the ideal mechanical advantage of this wheel and axle system when the resistance force is applied to the axle.
Formula, substitute, final answer​