What is Energy? • Energy is the ability or capacity to do work ○ Work is the process of moving an object • Energy is the ability or capacity to move an object Energy Transformations • Energy can be transformed from one type to another • You can transfer energy from one object to another by doing work • Work-Energy Theorem ○ Work done on a system by an external force changes the energy of the system Kinetic Energy • Kinetic Energy is energy of motion ○ The ability or capacity of a moving object to move another object • K=1/2 〖mv〗^2 Potential Energy • Potential Energy (U) is energy an object possesses due to its position or state of being ○ Gravitational Potential Energy (Ug) is the energy an object possesses because of its position in a gravitational field ○ Elastic Potential Energy (Us) ○ Chemical Potential Energy ○ Electric Potential Energy ○ Nuclear Potential Energy • A single object can have only kinetic energy, as potential energy requires an interaction between objects Internal Energy • The internal energy of a system include the kinetic energy of the objects that make up the system and the potential energy of the configuration of the objects that make up the system • Changes in a system’s structure can result in changes in internal energy Gravitational Potential Energy (Ug) Conservative Forces • A force in which the work done on an object is independent of the path taken is known as conservative force • A force in which the work done moving along a closed path is zero • A force in which the work done is directly related to a negative change in potential energy (W=-ΔU) Conservative Forces Non-Conservative Forces Gravity Elastic Forces Friction Drag Air Resistance Coulombic Forces Newton’s Law of Universal Gravitation • The gravitational force of attraction between any two objects with mass • F_g=−(〖Gm〗_1 m_2)/r^2 r ̂ Force from Potential Energy Summary
