Question

if velocity is positive, which would most likely yield a negative acceleration? a final velocity that is faster than an initial velocity. a time that is less than a half hour. an initial velocity that is faster than a final velocity. a time that is greater than a half hour.

Explanation:

Acceleration is calculated as $a=\frac{v_f - v_i}{t}$, where $v_f$ is final velocity, $v_i$ is initial velocity and $t$ is time. When $v_i>v_f$, the numerator $v_f - v_i$ is negative. Since time $t$ is positive, acceleration $a$ is negative. Time values alone do not determine the sign of acceleration. If final velocity is faster than initial velocity, acceleration is positive.

Answer:

C. An initial velocity that is faster than a final velocity.