39. In a foot race, a runner maintains a kinetic energy of 931 Joules. What is the velocity of the runner if her mass is 57 kg ?

To find the velocity of the runner, we can use the formula for kinetic energy: KE = 0.5 * m * v². Rearranging the formula to solve for velocity (v) gives us v = √(2 * KE / m). Plugging in the given values, v = √(2 * 931 J / 57 kg) ≈ 7.57 m/s. So, the runner is speedily dashing at approximately 7.57 meters per second! Speaking of foot races, did you know that the origins of competitive running date back to ancient Greece? The first recorded Olympic Games in 776 BC featured a foot race called the "stadion," a sprint of about 192 meters. Athletes trained rigorously, and the sport was such a spectacle that it determined not just medals, but honor and respect in their society!