Energy, Work And Power
Übersicht
Nothing happens without energy being shifted from one store to another. A falling diver, a glowing bulb, a sprinting athlete, a charging phone: each is energy moving from where it was kept to somewhere new. The grand rule that ties it all together is that the total never changes, only its form and location.
In this lesson you will name the energy stores, describe how energy is transferred by forces, currents, heating and waves, and use the principle of conservation of energy to read flow and Sankey diagrams. You will also calculate kinetic energy, gravitational potential energy, work and power, always showing the equation, the substitution and the answer with units.
Ziele
- State that energy may be stored as kinetic, gravitational potential, chemical, elastic (strain), nuclear, electrostatic and internal (thermal)
- Describe how energy is transferred between stores during events and processes, including examples of transfer by forces (mechanical work done), electrical currents (electrical work done), heating, and by electromagnetic, sound and other waves
- Know the principle of the conservation of energy and apply this principle to simple examples including the interpretation of simple flow diagrams
- [Supplement] Recall and use the equation for kinetic energy Eₖ = ½mv²
- [Supplement] Recall and use the equation for the change in gravitational potential energy ∆E = mg∆h p
- [Supplement] Know the principle of the conservation of energy and apply this principle to complex examples involving multiple stages, including the interpretation of Sankey diagrams
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Unterrichtsbewertung
Herzlichen Glückwunsch zum Abschluss der Lektion über Energy, Work And Power. Jetzt, da Sie die wichtigsten Konzepte und Ideen erkundet haben,
Sie werden auf eine Mischung verschiedener Fragetypen stoßen, darunter Multiple-Choice-Fragen, Kurzantwortfragen und Aufsatzfragen. Jede Frage ist sorgfältig ausgearbeitet, um verschiedene Aspekte Ihres Wissens und Ihrer kritischen Denkfähigkeiten zu bewerten.
Nutzen Sie diesen Bewertungsteil als Gelegenheit, Ihr Verständnis des Themas zu festigen und Bereiche zu identifizieren, in denen Sie möglicherweise zusätzlichen Lernbedarf haben.
- Which is NOT an energy store? A. chemical B. heating C. elastic (strain) D. gravitational potential Answer: B
- A 2 kg ball moves at 10 m/s. Its kinetic energy is A. 10 J B. 20 J C. 100 J D. 200 J Answer: C
- A 5 kg mass is lifted 4 m (g = 9.8 N/kg). The gain in gravitational potential energy is A. 20 J B. 49 J C. 196 J D. 200 J Answer: C
- A force of 20 N moves a box 3 m in the direction of the force. The work done is A. 6.7 J B. 23 J C. 60 J D. 600 J Answer: C
- A motor does 800 J of work in 4 s. Its power output is A. 0.005 W B. 200 W C. 800 W D. 3200 W Answer: B
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Empfohlene Bücher
Weiterlernen mit offenen Quellen
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Lehrbuchabschnitt
Conservation of Energy
Energy, as we have noted, is conserved, making it one of the most important physical quantities in nature. The law of conservation of energy can be stated as follows: Total energy is constant in any process. It may change in form or be transferred from one system to another, but the total remains th
"College Physics: Conservation of Energy" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/college-physics/pages/7-6-conservation-of-energy. Access for free at https://openstax.org/books/college-physics/pages/1-introduction
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Lehrbuchabschnitt
Conservative Forces and Potential Energy
Work is done by a force, and some forces, such as weight, have special characteristics. A conservative force is one, like the gravitational force, for which work done by or against it depends only on the starting and ending points of a motion and not on the path taken. We can define a potential ener
"College Physics: Conservative Forces and Potential Energy" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/college-physics/pages/7-4-conservative-forces-and-potential-energy. Access for free at https://openstax.org/books/college-physics/pages/1-introduction
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