A person falls flat on their back on some slippery ice and is unconscious for a second. The horizontal position of their legs torso and head from their feet is given by 0.45 m, 0.92 m and 1.75 m respectively and their weights are 30 kg 50 kg and 10 kg. They try to sit up on the ice which is so slippery they are not able to move their horizontal centre of mass. The new positions of their legs, torso and head from their feet are 0.25 m, 0.59 m and 0.7 m. What is the magnitude of the change in position of the person's feet