An isotonic contraction can be concentric, which is where the muscle shortens as the fibres contract or eccentric, where the fibres contract as the muscle lengthens. When a muscle contracts with no resulting movement, it is an isometric contraction. Page: 1  1. 2  2. 3  3. 4  4. 5  5. 6  Back.
how much propane will i use i will be building an ig pool and ig spa 7ft spa i will be heating the spa with a 400k btu propane heater i would like to heat the pool a couple of time per year for special events local code limits the size of a propane tank to 125 gallons anything bigger will require a permit from the fire dept
Here, 133,280 divided by 266,000 yields a heat-up time of .5 hours, or 30 minutes. Conversely, if the customer has a specific heating time in mind â say, 30 minutes â the formula works thusly: 133,280 Ã· .5 = 266,000 BTUs. In other words, a 400-gallon spa would need a heater with an output of 266,000 BTUs to heat the water in 30 minutes.