Remember that the force necessary to move an object over a horizontal surface is the weight of the object multiplied by the coeficient of friction, an the formula is this:
Where u is the coefficient of static friction and N is the normal force, or in this case the weight of the object so if we solve for U the formula would be like this:
Static friction is the friction that exists between two or more solids that are not moving with a relative speed. To calculate the static friction coefficient we use the formula Fs=us × n where Fs is the static friction , us is the coefficient of static friction and the n is the normal force. thus the coefficient of static friction will be 5 N÷ 25 N = 0.2 Hence 0.2 is the coefficient of static friction