A car accelerates uniformly from rest to 20 m s-1 in 8 s. The distance covered is

Explanation

With uniform acceleration from rest the average velocity is half the final velocity, which is 10 m s-1, and over 8 s that gives 80 m. The same answer comes from finding a as 20 divided by 8, which is 2.5 m s-2, then using S equal to half a t squared. Using the final velocity of 20 m s-1 for the whole 8 s gives the wrong answer of 160 m.