$1)-$blanck question

$1.$ The three elements of a force acting on a rigid body are: the magnitude,and line of action ofthe force

$2.$ If objects in contact with each other slide or tend to slide, there is resistance on the contact surface, which is called the $.$

$3.$ Translation is a special case in which the body moves that any line in the body remains To its initial position.

$4.$ The motion of the moving point relative to the fixed reference frame is called the motion.

$5.$ motion.of a material body is the energy due to the motion, which is a measure of the mechanical