This essay focuses on the angle between two bones or body surfaces. 30 mm anterior to the axis of rotation (atlanto-occipital joint, B) acting at an angle of 90°.

the angle between two bones or body surfaces

on a applied physics question and need guidance to help me learn.
The mass of matts head is 5 kg and its centre of mass (A) is located LHead = 30 mm anterior to the axis of rotation (atlanto-occipital joint, B) acting at an angle of 90°. The neck extensors act LNeck = 52 mm posterior to the axis of rotation, at an angle of ????a movement of a joint that increases the angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed (bent) elbow. Straightening of the arm would require extension at the elbow joint. If the head is tilted all the way back, the neck is said to be extended.

The brachioradialis is a paradoxical muscle. Its origin and innervation are characteristic of an extensor muscle, but it is actually a flexor at the elbow.

The muscle is most visible when the forearm is half pronated, and flexing at the elbow against resistance.

In the distal forearm, the radial artery and nerve are sandwiched between the brachioradialis and the deep flexor muscles.

θ
= 128°. Matt is currently holding his head still. How much force do the neck extensor muscles need to produce to keep the head from nodding (i.e. keep his head still). Assume gravity is 9.8 m.s-2?

Details;

Firstly, plan

Secondly, be cautious

Thirdly, be creative

Further, be innovative