Conclusion (appendix: mechanics analysis picture)
I Pulling force = foot and force of maximum static friction (positive pressure of foot and floor × friction ratio)
II Factors:
Height of rope: Less effort is used, lower the rope is;
Supporting angle: smaller the angle is, the bigger the pulling is;
Dragging arm: shorter the arm is, less effort it needs;
Potential energy transfers to energy of motion: force of power arm increases, then horizontal pulling power increases;
Pedal force of leg: bigger pedal force is, bigger horizontal component force is;
Material of shoe sole: bigger ratio of friction is, more stable upper of a shoe is, bigger pulling force it bears;
Body: stronger, bigger the gripping force is, stronger the holding force is.
III Best Status and Potentiality
Horizontal pulling force based on different holding angle:
30 degree pulling force = 19/20×G×√3
45 degree pulling force＝19/20×G
60 degree pulling force＝19/20×G×√3÷3