When you come into class, sometimes your chair feels warm. Why is that? How did it get warm? (heat/temperature/thermal energy)

Shy diving is the only sport which doesnot require a high level of physical fitness

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.