Why do sprinters wear spiked shoes for running? Check out the Sprinter SIM at Learn more about Friction at View all of CK-12’s free, high-quality STEM resources at

Each swing may be unique, but they all require potential and kinetic energy to get the ball moving. USGA equipment researchers tell how energy, and its transfer, makes each golf shot possible. Visit www.NBCLearn.com for more. For daily updates from…