## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

The distance traveled is proportional to the square of the time. The square of $2.0~s$ is $4.0~s^2$ and the square of $4.0~s$ is $16~s^2$. Since the square of $4.0~s$ is four times the square of $2.0~s$, the distance traveled in the first four seconds will be four times the distance traveled in the first two seconds. Since $4\times 2.0~furlongs$ is $8.0~furlongs$, the distance traveled in the first four seconds is 8.0 furlongs.