A student tries to derive the equation for kinetic energy $E_K$. She starts with an object of mass $m$ that is initially stationary. A constant force $F$ acting on the object makes it accelerate from rest to a final speed $v$ over a displacement $s$. The kinetic energy gained by the object equals the work done on it by force $F$. Which equation does the student not need when deriving the formula for $E_K$?
- A$F = ma$
- B$W = Fs$
- C$E = \frac{1}{2}Fs$
- D$v^2 = u^2 + 2as$