Questions | 5 |

Focus | Energy, Work, & Power |

Topics | Kinetic Energy, Power, Work |

Question Type | Questions |

Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: \(KE = {1 \over 2}mv^2\) where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE **linearly** while an increase in speed increases KE **exponentially**.

Power is the rate at which work is done, **P = w/t**, or work per unit time. The **watt (W)** is the unit for power and is equal to 1 joule (or newton-meter) per second. **Horsepower (hp)** is another familiar unit of power used primarily for rating internal combustion engines. A 1 hp machine does 550 ft⋅lb of work in 1 second and 1 hp equals 746 watts.

Work is accomplished when force is applied to an object: **W = Fd** where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done.