Difference between revisions of "Work"
m (Reverted edits by StinkyCheese9 (Talk); changed back to last version by Sandalphon) |
m (Maths formatting) |
||
| (15 intermediate revisions by 8 users not shown) | |||
| Line 1: | Line 1: | ||
| − | In [[physics]], work refers to the product of [[force]] and [[distance]] vectors | + | In [[physics]], '''work''' refers to the [[dot product]] of [[force]] and [[distance]] vectors |
| − | <ref>Serway and Beichner, ''Physics for Scientists and Engineers'', Fifth Edition</ref> | + | .<ref>Serway and Beichner, ''Physics for Scientists and Engineers'', Fifth Edition</ref> |
| − | + | <math>W = \vec{F} \cdot \vec{d}</math> | |
Or: | Or: | ||
| − | + | <math>W = Fd \cos{\theta}</math> | |
| − | Where θ is the angle that separates the vectors. The second form of the equation is the expanded form of the "dot product" in the first equation. In physics, the dot product | + | Where θ is the angle that separates the vectors. The second form of the equation is the expanded form of the "dot product" in the first equation. In physics, the dot product <math>\vec{a} \cdot \vec{b}</math> (read "a dot b") can be rewritten as <math>|\vec{a}| |\vec{b}| \cos{\theta}</math>. |
| − | + | When the force is not constant, the correct expression uses [[integration]]: | |
| − | Its units are that of force multiplied by distance, in SI this is [[newton (unit)|Newton]] · [[Meter]], or [[Joule]] | + | <math>\int \vec{F} \cdot \mathrm{d}\vec{s}</math> |
| + | |||
| + | Work is a transfer of [[energy]]; if <math>W</math> is positive, there is a transfer of energy ''to'' the system, and if <math>W</math> is negative there is a transfer of energy ''from'' the system. | ||
| + | |||
| + | Its units are that of force multiplied by distance, in SI this is [[newton (unit)|Newton]] · [[Meter]], or [[Joule]]. The aberrant unit kWh (kilowatt-hour) is sometimes used; this unit is the product of kilowatt, or 1,000 Watts (Joules per second), and hour, or 3,600 seconds. | ||
==References== | ==References== | ||
<references/> | <references/> | ||
| − | [[ | + | [[Category:Physics]] |
[[Category:Mechanics]] | [[Category:Mechanics]] | ||
Latest revision as of 21:12, December 13, 2016
In physics, work refers to the dot product of force and distance vectors .[1]
<math>W = \vec{F} \cdot \vec{d}</math>
Or:
<math>W = Fd \cos{\theta}</math>
Where θ is the angle that separates the vectors. The second form of the equation is the expanded form of the "dot product" in the first equation. In physics, the dot product <math>\vec{a} \cdot \vec{b}</math> (read "a dot b") can be rewritten as <math>|\vec{a}| |\vec{b}| \cos{\theta}</math>.
When the force is not constant, the correct expression uses integration:
<math>\int \vec{F} \cdot \mathrm{d}\vec{s}</math>
Work is a transfer of energy; if <math>W</math> is positive, there is a transfer of energy to the system, and if <math>W</math> is negative there is a transfer of energy from the system.
Its units are that of force multiplied by distance, in SI this is Newton · Meter, or Joule. The aberrant unit kWh (kilowatt-hour) is sometimes used; this unit is the product of kilowatt, or 1,000 Watts (Joules per second), and hour, or 3,600 seconds.
References
- ↑ Serway and Beichner, Physics for Scientists and Engineers, Fifth Edition