Cycle per second Cycle per second The cycle per second was a once-common English name for the unit of frequency now known as the hertz (Hz). The plural form was typically used, often written cycles per second, cycles/second, c.p.s., c/s, ~, or, ambiguously, just cycles. The term comes from the fact that sound waves have a frequency measurable in their number of oscillations, or "cycles", per second. With the organization of the International System of Units in 1960, the cycle per second was officially replaced by the hertz, or reciprocal second, "s" or "1/s". Symbolically, "cycle per second" units are "cycle/second", while hertz
Vibration white finger to 25m/s². HSE publishes a list of typically observed vibration levels for various tools, and graphs of how long each day a worker can be exposed to particular vibration levels. This makes managing the risk relatively straightforward. Tools are given an Exposure Action Value (EAV, the time which a tool can be used before action needs to be taken to reduce vibration exposure) and an Exposure Limit Value (ELV, the time after which a tool may not be used). In the United States, the National Institute for Occupational Safety and Health published a similar database where values for sound power