Question

select the correct answer.
a car accelerates from rest to a velocity of 5 meters/second in 4 seconds. what is its average acceleration over this period of time?
a. its acceleration is 1.25 meters/second.
b. its acceleration is 5 meters/second.
c. its acceleration is 0.8 meters/second.
d. its acceleration is 1.25 meters/second².
e. its acceleration is 20 meters.

Explanation:

Step1: Recall average acceleration formula

Average acceleration is $\bar{a} = \frac{\Delta v}{\Delta t} = \frac{v_f - v_i}{t_f - t_i}$

Step2: Identify given values

Initial velocity $v_i = 0$ m/s (starts from rest), final velocity $v_f = 5$ m/s, time $\Delta t = 4$ s

Step3: Substitute values into formula

$\bar{a} = \frac{5 - 0}{4} = \frac{5}{4} = 1.25$ m/s²

Step4: Match with correct option

The result has units of meters/second², which matches option D.

Answer:

D. Its acceleration is 1.25 meters/second².