Partial Credit

This mural is funny because Calvin (from Calvin and Hobbes comics) doesn't know how to solve the physics problem, but he can still get partial credit by copying equations from the equation sheet (or maybe by remembering them, depending on if his class has an equation sheet like ours). Some of the equations he wrote would not help him solve the problem, but it doesn't hurt to write them. It's also funny because it is true that if you're stuck on a problem on a physics test, writing equations may get you partial credit, and equations are a good place to start any physics problem.

Calvin should really solve the problem by setting the sum of forces in the vertical and horizontal directions equal to ma: N+Fsin(theta)-mg=0 (no vertical acceleration), Fcos(theta)-f=ma, friction = mu*normal = u(mg-Fsin(theta)) according to the vertical direction equation. Then, he could solve for F in terms of the other variables.