← Unit 2: Newton's Laws of Motion
Newton's Second Law with Variable Forces
When force depends on position or velocity (like drag or spring forces), Newton's second law becomes a differential equation requiring calculus to solve.
Overview
F(x) = m(d²x/dt²) or F(v) = m(dv/dt). Unlike Physics 1's constant-acceleration formulas, Physics C requires setting up and solving (or at least analyzing) differential equations when force isn't constant.
Practice Quiz
Question 1 of 1Score so far: 0/0
An object experiences a drag force proportional to its velocity, F=-bv. Why can't the simple kinematic equations (like v=v₀+at) be used here?