- Asked 2/15
- 2073 Magh · 4 marks
- 2069 Bhadra · 4 marks
Stored vs transient energy; total energy
Short answer
Stored energy is energy possessed within a system as a property (state function), e.g., internal, kinetic, potential energy. Transient energy, like heat and work, crosses the boundary during interactions, is not a property, and is path-dependent. Total energy E = U + KE + PE.
Explain the differences between stored energy and transient energy with examples. Also define total energy.
Energy of a system exists in two ways: stored in the system (a property) or in transit across its boundary.
| Basis | Stored energy | Transient (transit) energy |
|---|---|---|
| Meaning | Energy possessed by the system within its boundary | Energy that crosses the boundary during a process |
| Is it a property? | Yes (state function) | No (path function) |
| Exists | At any state of the system | Only during the interaction |
| Differential | Exact, dE | Inexact, δQ, δW |
| Examples | Internal energy U, kinetic energy ½mV², potential energy mgz | Heat Q, work W (also energy carried by mass in open systems) |
Example: Hot water in a closed tank has stored internal energy. If the tank is heated through its wall, the heat Q is transient energy; once it enters, it is stored as increased internal energy. Stirring the water with a paddle is work, also transient, which then appears as stored internal energy.
Total energy
Total energy E of a system is the sum of all forms of energy stored in it:
E = U + KE + PE (+ chemical, nuclear, electrical, etc. if present)
where U = internal energy, KE = ½mV², PE = mgz. On a unit mass basis: e = u + V²/2 + gz. For a stationary system, E = U.
✓ Answer checked by Claude Opus 5.5 (high effort)
Related questions
- Nitrogen piston with stops: work and heat · Fundamental of Thermodynamics & Heat Transfer, chapter 4
- Energy stored in parallel capacitors · Engineering Physics, chapter 7
- Energy stored in an inductor · Engineering Physics, chapter 8 · asked 4×
- Energy stored in coil, time constants · Engineering Physics, chapter 8
- Energy stored for given potential field · Electromagnetism, chapter 2
All Fundamental of Thermodynamics & Heat Transfer chapter 2 questions →