F Vector is parallel to r vector formula ?

[thekey]

Hi everyone( the force vector parallel to the position vector r ) = Force vector* (r vector / r)

I don't know how did they find this relation ?
it seems to me they multiplied F hat by the unit vector ?
why ??
I am just confused about it

any idea ??

 

[thekey]

F parallel hat= (F hat) * (r hat / r)

 

[thekey]

the projection of v into the direction of u

0k that's why :)

thanks