After 30 s, a runner is sprinting at 3 m/s. But, 10 s later, the runner is sprinting at 3.8 m/s. What is the runner's acceleration during this time?
We can consider that the runner did an acceleration of 0.8 m.s during the 10 seconds of difference. We can deduce that the runner did an acceleration of 0.08 m.s every second during this time.