Physics is F=uN!

The rather nerdy boy thinks that physics is fun because he goes to soccer games (Mr. Curtis the physics teacher is also a soccer coach) and impresses pretty cheerleaders with his physics knowledge. Various forces being exerted by the different people are drawn. F=uN is the equation for the force exerted by (kinetic) friction (static friction is F<=uN), where F is the force of friction, u is mu is the coefficient of friction, and N is the normal force (of the surface where there is friction).