A student bends her head at 40.0° from the vertical while intently reading her physics book, pivoting the head around the upper vertebra (point P in Fig. E11.23). Her head has a mass of 4.50 kg (which is typical), and its center of mass is 11.0 cm from the pivot point P. Her neck muscles are 1.50 cm from point P, as measured perpendicular to these muscles. The neck itself and the vertebrae are held vertical.

(a) Draw a free-body diagram of the student€™s head.

(b) Find the tension in her neck muscles. 

Figure e11.23

Transcribed Image Text:

40° Center of mass of head - 1.50 cm Neck muscles Vertebrae 11.0 cm