AP Physics 1 is a notoriously difficult class, and its page-long equation sheet does nothing to help incoming students. However, by the end of the year, many students begin to find their favorite topics, ranging from kinematics to simple harmonic motion. Some topics are inherently simpler; others are unavoidably fear-inducing (rotational motion, anyone?). Nonetheless, at the end of the year, there are some equations that remain much more preferred over others.
WARNING: SPOILERS AHEAD
1) vx=vx0+axt
One of the absolute classics of AP Physics 1, the equation for velocity with constant acceleration is one of the first equations taught in the class. Out of the three kinematics equations on the Green Sheet, this one is far the simplest. Equations don’t get any more easy to understand than this, and every AP Physics student knows that using this equation means a simple problem. Of course, the only downside is that the College Board throws in the little subscripts just to be confusing (even though the equation itself is simple).
2) v1i–v2i=v2f–v1f
Another classic equation from AP Physics 1 is the equation for finding velocity in an elastic collision. Unlike the previous equation, there is nothing easy about this equation: whenever a problem with an elastic collision comes up, every AP Physics student knows to get ready for a menace of a problem. However, Mr. Spangenberg’s miniature song “one minus two equals two minus one, doo doo doo” makes it more memorable every time one of these brutal questions pops up. It is also one of the few equations that Mr. Spangenberg does not derive.
3) ω=ω0+αt
Although this equation is from Rotational Motion, it is arguably the simplest concept from the entire unit. It is identical to the equation for velocity with constant acceleration, except replacing velocity with angular velocity and acceleration with angular acceleration. The rest of Rotational Motion becomes complicated (rotational inertia, torque, etc), but whenever this equation comes up, the problem is bound to be easy. In a sense, all three of the rotational kinematics equations are considered “easy” relative to the difficulty of the rest of the unit.
4) ρ=mV
New this year, the density equation has moved from the AP Physics 2 equation sheet to AP Physics 1. Regardless of where it is, this equation is one of the absolute easiest to use and most intuitive of all of the equations. The Greek letters give it a scary look, but at its core, it simply defines density. This simple equation is used abundantly throughout the Fluids unit, but unfortunately, College Board often turns questions involving density into multi-step problems requiring buoyant force or Bernoulli’s equation.
5) Fnet=ma
Straight from Newton’s Second Law, F=ma pops up in the third unit of AP Physics, Dynamics. Although it appears relatively simple, its applications only get harder as the year goes on. The entire unit is essentially based on this one equation, whether that is a box on a ramp or a man carrying groceries. When Newton “invented” it, this one equation arguably became the foundation of physics. As one of the few physics concepts that newcomers walk into Mr. Spangenberg’s room knowing, this equation warrants respect.
6) The Full Form of the Conservation of Energy
Seeing Mr. Spangenberg write out the full form of the conservation of energy equation for the first time is absolutely terrifying. The equation is a mile long, and none of it makes any sense. Over the course of the unit, the equation gradually becomes clearer and clearer, but it still feels frightening. By the end of the year, most students understand energy and don’t need to write out the whole equation, but this equation still qualifies as a Top 6 AP Physics 1 equation out of the sheer amount of fear that it induces.
