Question

A car moving south speeds up from 10 m/s to 40 m/s in 15 seconds. What is the car's acceleration?

Answer 1

Answer: $2m/s^{2}$

Explanation:

Assuming the car is moving only in one direction (to the South), its acceleration $a$ is given by the following formula, which expresses the variation of the velocity in time:

$a=\frac{\Delta V}{\Delta t}$   (1)

Where:

$\Delta V=V_{2}-V_{1}=40m/s-10m/s=30m/s$   is the variation in velocity

$\Delta t=t_{2}-t_{1}=15s-0s=15s$ is the variation in time

Rewritting (1) with the calculated values:

$a=\frac{30m/s}{15s}$   (2)

$a=2m/s^{2}$  This is the acceleration of the car