I agree substantially with Jason in USMA 21168 and Marcus in USMA 21181 > James Wentworth wrote: >>The Hz is already used in engineering to denote one rotation. When I was >>helping the Poker Flat Research Range obtain a number of surplus Hydra-70 70 >>mm aircraft rockets from the US Army, I noticed in the performance >>specifications that the rockets' roll rate was expressed in Hz. The hertz >>is a perfect "drop-in" replacement for rpm. I think it isn't used more >>frequently in mechanical engineering because non-electrical engineers think >>of it as an electrical unit (just as many American MEs are reluctant to rate >>combustion engine power in watts because "everybody knows the watt is an >>electrical unit."). It's a matter of incorrect perception stemming from >>ignorance. -- Jason >> >>----- Original Message ----- >>From: Ma Be <[EMAIL PROTECTED]>
>>> I feel quite strongly that rpm is also another... "idiocy" we could do >>without (sorry, couldn't find a better adjective for it). If we are to >>think of this property as "periodical" we could certainly think of replacing >>it with Hz (or a prefixed "version" of it, like cHz or mHz). If we think of >>"rotational speed" (in angular form) then we'd be talking about this in >>rad/s, I'd think. The hertz is simply s^-1. It is generally used for repetative phenomena; e.g. x rev/second = x rev.hertz. The term "rev" is usually omitted as understood. In the case of rad/s the term "rad" would necessary; e.g. x rad/s = x rad.Hz. In the case of automobiles, 6000 rpm = 100 rev/s = 100 Hz. Joseph B.Reid 17 Glebe Road West Toronto M5P 1C8 Tel. 416 486-6071
