Classification: Unclassified > Is Isp to be expressed in units of seconds or in meters/second? I chose units > of seconds. Under SI (AKA the metric system) Isp *is* expressed in seconds, NOT m/s. I just looked it up in "Quantities and Units of Measurement" by JV Drazil Alex Aplin "Personal e-mail. This e-mail is personal. It is not authorised or sent on behalf of Dstl. This e-mail is the personal responsibility of the sender." "The remarks in this e-mail are personal and do not represent Dstl or Government policy." "This e-mail and any attachment(s) is intended for the recipient only. Its unauthorised use, disclosure, storage or copying is not permitted. Communications with Dstl are monitored and/or recorded for system efficiency and other lawful purposes, including business intelligence, business metrics and training. Any views or opinions expressed in this e-mail do not necessarily reflect Dstl policy." "If you are not the intended recipient, please remove it from your system and notify the author of the email and centralenq@xxxxxxxxxxx"