A car starts from rest and accelerates uniformly, covering 60 m in 6 s. What is its acceleration?

• A. 5 m/s^2
• B. 10/3 m/s^2
• C. 1 m/s^2
• D. 0 m/s^2

Answer: (B)

Understanding what constant acceleration from rest does to distance helps here. With uniform acceleration from rest, the distance covered in time t is s = (1/2) a t^2. Here s = 60 m and t = 6 s, so 60 = (1/2) a (6)^2 = 18a, giving a = 60/18 = 10/3 m/s^2 (about 3.33 m/s^2).

Another quick check: the average speed is s/t = 60/6 = 10 m/s. For constant acceleration from rest, the final speed is twice the average speed, so v_final = 20 m/s, and a = v_final/t = 20/6 = 10/3 m/s^2.

The other options would produce different distances for the same time, so they don’t fit.