The formula for solving friction is F = ma, where F represents the force of friction, m represents the mass of the object, and a represents the acceleration.
Fk stands for the force of kinetic friction, which is the resistance force that opposes the motion of an object when it is already in motion.
u represents the coefficient of friction, which is a measure of the roughness or smoothness of the surface. Fn represents the normal force, which is the force exerted by a surface on an object that is in contact with it. Together, u*Fn represents the maximum force of static friction, which is the force that must be overcome to set an object in motion.
The coefficient of friction can be calculated by dividing the force of friction (F) by the normal force (Fn): u = F/Fn. It can also be determined experimentally by measuring the force required to move an object and dividing it by the normal force.
The units for the force of friction (F) and the force of kinetic friction (Fk) are typically measured in Newtons (N). The mass (m) is measured in kilograms (kg) and the acceleration (a) is measured in meters per second squared (m/s^2). The coefficient of friction (u) and the normal force (Fn) do not have specific units, but their values are typically given in decimal form.