As shown in figure CQ5.22, student A, a 55 kg girl, sits on one chair with metal runners, at rest on a classroom floor. Student B, an 80 kgboy, sits on an identical chair. Both students keep their feet off the floor. A rope runs from student A’s hands around a light pulley and then over her shoulder to the hands of a teacher standing on the floor behind her. The low-friction axle of the pulley is attached to a second rope held by student B, all ropes run parallel to the chair runners.
- If student A pulls on her end of the rope, will her chair or will B’s chair slide on the floor? Explain why?
- If instead, the teacher pulls on his rope end, which chair slides? Why this one?
- If student B pulls on his rope, which chair slides? Why?
- Now the teacher ties his end of the rope to student A’s chair. Student A pulls on the end of the rope in her hands. Which chair slides and why?