find average acceleration

Question

An object is moving along the x axis. At t = 5.8 s, the object is at x = +3.0 m and has a velocity of +4.2 m/s. At t = 7.1 s, it is at x = +9.0 m and its velocity is -1.0 m/s. Find the average acceleration between t = 5.8 s and t = 7.1 s.

Answer 1

The average acceleration = change in velocity / change in time

change in velocity = -1.0 - 4.2 = -5.2 m/s

change in time = 7.1 - 5.8 = 1.3 s

so average acceleration = -5.2 / 1.3 = -4 m/s/s

Mike