Q2: A human-made object

Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work)

In an experiment examining the effects tai chi on arthritis pain, callahan (2010) selected a large sample of individuals with doctor-diagnosed arthritis. half of the participants immediately began a tai chi course and the other half (the control group) waited 8 weeks before beginning. at the end of 8 weeks, the individuals who had experienced tai chi had less arthritis pain that those who had not participated in the course.

Which type of stimulus do mechanoreceptors detect? sound pain heat light