How physical properties are important for identifying unknown substances

The desk has a weight of 75 lb and a center of gravity at g. determine the initial acceleration of a desk when the man applies enough force f to overcome the static friction at a and b. also, find the vertical reactions on each of the two legs at a and at b. the coefficients of static and kinetic friction at a and b are ms = 0.5 and mk = 0.2, respectively

Iwill give 30 points to whoever answers ! what is the formula for actual mechanical advantage and ideal mechanical advantage?

The two required components for a generator