Which of the following describes acceleration? a. acceleration cannot be described with a negative number. b. acceleration is a vector quantity. c. acceleration describes how displacement changes with time. d. the si units for acceleration are m/s.

The answer would be:

B. Acceleration is a vector quantity.

We can rule out the others because:

---Acceleration CAN be described with a negative number. The sign actually shows the direction. A negative number indicates a deceleration.

---Displacement change over time is the definition of velocity NOT acceleration.

---The SI unit for acceleration is m/s².

***A vector quantity is measure of magnitude and direction, which acceleration has.