What is the meaning of negative exponents in SI units?












1















Please could someone explain the reason for using negative superscripts in SI units, and more precisely when to use negative versus positive?



I do not understand, for example, why the volume of a fuel would be given in m3 but heat of combustion would be given in J m-3.










share|improve this question



























    1















    Please could someone explain the reason for using negative superscripts in SI units, and more precisely when to use negative versus positive?



    I do not understand, for example, why the volume of a fuel would be given in m3 but heat of combustion would be given in J m-3.










    share|improve this question

























      1












      1








      1








      Please could someone explain the reason for using negative superscripts in SI units, and more precisely when to use negative versus positive?



      I do not understand, for example, why the volume of a fuel would be given in m3 but heat of combustion would be given in J m-3.










      share|improve this question














      Please could someone explain the reason for using negative superscripts in SI units, and more precisely when to use negative versus positive?



      I do not understand, for example, why the volume of a fuel would be given in m3 but heat of combustion would be given in J m-3.







      mechanical-engineering






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Dec 28 '18 at 11:58









      tsvallendertsvallender

      1112




      1112






















          1 Answer
          1






          active

          oldest

          votes


















          5














          Negative exponents means per. In countries that were heavily influenced by the British, units such as meters per second would most likely be written $m/s$. In Europe and elsewhere it could be written with negative exponents as $m.s^{-1}$.



          In your example $J m^{-3}$ means joules per cubic meter.






          share|improve this answer























            Your Answer





            StackExchange.ifUsing("editor", function () {
            return StackExchange.using("mathjaxEditing", function () {
            StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
            StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
            });
            });
            }, "mathjax-editing");

            StackExchange.ready(function() {
            var channelOptions = {
            tags: "".split(" "),
            id: "595"
            };
            initTagRenderer("".split(" "), "".split(" "), channelOptions);

            StackExchange.using("externalEditor", function() {
            // Have to fire editor after snippets, if snippets enabled
            if (StackExchange.settings.snippets.snippetsEnabled) {
            StackExchange.using("snippets", function() {
            createEditor();
            });
            }
            else {
            createEditor();
            }
            });

            function createEditor() {
            StackExchange.prepareEditor({
            heartbeatType: 'answer',
            autoActivateHeartbeat: false,
            convertImagesToLinks: false,
            noModals: true,
            showLowRepImageUploadWarning: true,
            reputationToPostImages: null,
            bindNavPrevention: true,
            postfix: "",
            imageUploader: {
            brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
            contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
            allowUrls: true
            },
            noCode: true, onDemand: true,
            discardSelector: ".discard-answer"
            ,immediatelyShowMarkdownHelp:true
            });


            }
            });














            draft saved

            draft discarded


















            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fengineering.stackexchange.com%2fquestions%2f25276%2fwhat-is-the-meaning-of-negative-exponents-in-si-units%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown

























            1 Answer
            1






            active

            oldest

            votes








            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            5














            Negative exponents means per. In countries that were heavily influenced by the British, units such as meters per second would most likely be written $m/s$. In Europe and elsewhere it could be written with negative exponents as $m.s^{-1}$.



            In your example $J m^{-3}$ means joules per cubic meter.






            share|improve this answer




























              5














              Negative exponents means per. In countries that were heavily influenced by the British, units such as meters per second would most likely be written $m/s$. In Europe and elsewhere it could be written with negative exponents as $m.s^{-1}$.



              In your example $J m^{-3}$ means joules per cubic meter.






              share|improve this answer


























                5












                5








                5







                Negative exponents means per. In countries that were heavily influenced by the British, units such as meters per second would most likely be written $m/s$. In Europe and elsewhere it could be written with negative exponents as $m.s^{-1}$.



                In your example $J m^{-3}$ means joules per cubic meter.






                share|improve this answer













                Negative exponents means per. In countries that were heavily influenced by the British, units such as meters per second would most likely be written $m/s$. In Europe and elsewhere it could be written with negative exponents as $m.s^{-1}$.



                In your example $J m^{-3}$ means joules per cubic meter.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Dec 28 '18 at 12:25









                FredFred

                7,35132238




                7,35132238






























                    draft saved

                    draft discarded




















































                    Thanks for contributing an answer to Engineering Stack Exchange!


                    • Please be sure to answer the question. Provide details and share your research!

                    But avoid



                    • Asking for help, clarification, or responding to other answers.

                    • Making statements based on opinion; back them up with references or personal experience.


                    Use MathJax to format equations. MathJax reference.


                    To learn more, see our tips on writing great answers.




                    draft saved


                    draft discarded














                    StackExchange.ready(
                    function () {
                    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fengineering.stackexchange.com%2fquestions%2f25276%2fwhat-is-the-meaning-of-negative-exponents-in-si-units%23new-answer', 'question_page');
                    }
                    );

                    Post as a guest















                    Required, but never shown





















































                    Required, but never shown














                    Required, but never shown












                    Required, but never shown







                    Required, but never shown

































                    Required, but never shown














                    Required, but never shown












                    Required, but never shown







                    Required, but never shown







                    Popular posts from this blog

                    Probability when a professor distributes a quiz and homework assignment to a class of n students.

                    Aardman Animations

                    Are they similar matrix