Task: Text Categorization
Input (English): By the equivalence principle, a homogenous gravitational field is equivalent to this quantity. The time derivative of this quantity is jerk. In the kinematic equation for position as a function of time, this quantity is the coefficient of the time-squared term, because it is the second derivative of position. By Newton's Second Law, it is equal to force over mass. For 10 points, name this quantity that is the ""a"" in ""F equals m a. ""
Output (English): Science