Question

A car accelerates at a constant rate from zero to 25.9 m/s in 7.6 seconds and then slows to 15.4 m/s in 5 seconds. What is its average acceleration to the nearest tenth of a m/s2 during the entire time?What was the acceleration during the first acceleration period?

Answer 1

a1 =(V-Vo)/t = (25.9-0)/7.6 = 3.4 m/s^2.
a2 = (15.4-25.9)/5 = -2.1 m/s^2.

a=(a1+a2)/2=(3.4 + (-2.1))/2=0.65 m/s^2.