The law of conservation of energy (6-28)

Question 1 of 3

Question

Change in the $\textbf{kinetic energy}$ $K$ of an object during its motion

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Question

Change in the $\textbf{potential energy}$ $U$ associated with an object during its motion

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Question

Change in the $\textbf{internal energy}$ $E_{\mathrm{other}}$ during an object's motion

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Review

Equation 6-28 suggests that we broaden our definition of energy to include both total mechanical energy $(E = K + U)$ and internal energy $E_{\mathrm{other}}$ . In this case, we have to expand the system to include not only the object and the sources of the conservative forces that produce $\Delta{U}$ , but also the sources of the nonconservative forces that result in $\Delta{E}_{\mathrm{other}}$ (like your hand in the case of the thrown pencil). As the object moves, $K$ , $U$ , and $E_{\mathrm{other}}$ can all change values, but the sum of these changes is zero: One kind of energy can transform into another, but the total amount of energy of all forms remains the same. This is the most general statement of the $\textbf{law of conservation of energy}$ .