Answer & Explanation:
In physics, a contact force is a force that acts at the point of contact between two objects, in contrast to body forces. Contact forces are described by Newton's laws of motion, as with all other forces in dynamics. Contact force is the force in which an object comes in contact with another object. Contact forces are also direct forces. Contact forces are ubiquitous and are responsible for most visible interactions between macroscopic collections of matter. Pushing a car up a hill or kicking a ball or pushing a desk across a room are some of the everyday examples where contact forces are at work. In the first case the force is continuously applied by the person on the car, while in the second case the force is delivered in a short impulse.
The lattice structure of Lithium Fluoride (LiF) is comprised of positively charged lithium ions (Li+) and negatively charged fluoride ions (F-) that a linked together by ionic bonds.
The crystal structure of LiF corresponds to that of a face centered cubic (FCC) lattice with Li+ and F- ions occupying the lattice points in the unit cell.
I don't know but look on the internet or use a calculator
