Work - energy transferred between systems
The amount of energy that is transferred between so-called ‘physical systems’ is called work. We can speak about it in the context of mechanical processes (we speak about work in progress and rotation), thermodynamic processes (generalised and volumetric work) and electric current. If we speak of work as moving a body a certain distance using a force, then work is expressed as the product of that force and distance. This formula for work is the most straightforward. The unit of work is the joule, denoted by the symbol J.
Work in mechanical processes
A more complicated version of the work formula is one where we consider work to be the scalar product of an applied force vector and a displacement vector. Only if the vectors are arranged in parallel can the work formula be simplified to the previous one. However, if the cosine of the angle between the vectors is not equal to 1, we must take then this fact into account in our calculations. After that, we multiply the value of the force used, the displacement and the cosine of the angle mentioned above. If the force used has changed, then its value on the way should be averaged. Quite
Work in the case of an electric current
If we are talking about an electric current, then the formula for work presents itself differently. The electric charge is multiplied by the voltage or potential difference – this formula determines how much work a 1,000-watt electric device will do in one hour. In the case of electricity, the formula for work comes from the definition of work – i.e., the change in potential energy within a conductor, the transfer of electric charge between points that have a different electric potential from each other.
Key takeaway
Formula for work: What is the work formula like How do you apply it properly We clarify and explain the work formula. Read our compendium.
When to use it?
List the physical quantities together with units.
Answer check
- List the physical quantities together with units.
- Write the formula for "Formula for work" and rearrange it before substituting numbers.
- After calculating, check the unit and the order of magnitude.
User-focused answer
Formula for work: What is the work formula like How do you apply it properly We clarify and explain the work formula. Read our compendium. Use this topic when the task asks for more than a name: you must identify the condition, choose the rule and justify the result.
When this topic is actually needed
Use this topic when the task asks for more than a name: you must identify the condition, choose the rule and justify the result. Formula for work: quantity, unit and relationship. Start with one clear definition sentence, then show the rule, and only then substitute the data.
The most common mistake is remembering the term but ignoring the condition in the task. If the answer has a unit, keep the unit with every number; if it is a language or glossary topic, show the term in a full sentence.
Complete way to work with the topic
- name the given data and the unknown
- write the definition or relationship
- test it on a simple example
- check the unit, range or sentence meaning
If the answer has a unit, keep the unit with every number; if it is a language or glossary topic, show the term in a full sentence. Start with one clear definition sentence, then show the rule, and only then substitute the data. If the answer has a unit, keep the unit with every number; if it is a language or glossary topic, show the term in a full sentence.
Worked example with commentary
Formula for work: Start with one clear definition sentence, then show the rule, and only then substitute the data. If the answer has a unit, keep the unit with every number; if it is a language or glossary topic, show the term in a full sentence.
| User-focused answer | What to remember |
|---|---|
| When this topic is actually needed | quantity, unit and relationship |
| Mistakes that usually weaken the answer | The most common mistake is remembering the term but ignoring the condition in the task. |
| Complete way to work with the topic | If the answer has a unit, keep the unit with every number; if it is a language or glossary topic, show the term in a full sentence. |
Mistakes that usually weaken the answer
The most common mistake is remembering the term but ignoring the condition in the task. The most common mistake is remembering the term but ignoring the condition in the task. Start with one clear definition sentence, then show the rule, and only then substitute the data.
Explain the topic in your own words. Create an example that shows when the rule can be used. Name one possible mistake and correct it.
Check exercises
- Explain the topic in your own words.
- Create an example that shows when the rule can be used.
- Name one possible mistake and correct it.
What to remember: Formula for work. Use this topic when the task asks for more than a name: you must identify the condition, choose the rule and justify the result. Start with one clear definition sentence, then show the rule, and only then substitute the data.