This does happen to many people and they suffer a lot of pain. The bones then rub against each other every time the joint is moved.
Cartilage keeps bones from rubbing together and provides a smooth surface for movement at the joints
Articular cartilage.
Cartilage
This connective tissue are called ligaments. Ligaments connect bones to bones while tendons connect muscles to bones. They are exactly the same tissue but terminology makes the names different.
cartilage
Dry ball joints/suspension joints. Universal joints going bad. Worn brake pad "squealers".
Types of cartiliginous joints: Synchondrosis Symphysis Synchondrosis joint has bands of hyaline cartilage which unite bones and an epiphyseal plate (temporary). For example between manubrium and first rib (synarthrotic). Symphysis joint has a pad of fibrocartilage between bones. For example the pubis symphysis and the joint between bodies of vertebrae. (amphiarthrotic).
Hey
1st Law
No, the two are spaced enough that it is fairly comfortable to use either one.
No, you can not get this model of laptop with a number pad because it's not big enough to fit one. You can get other laptops that have them though.
It can hold the brake pad against the rotor disc and cause premature failure and if it gets hot enough from friction, start a fire.