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In everyday use and in kinematics, the speed (commonly referred to as v) of an object is the magnitude of the rate of change of its position with time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero.
Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or, in the US and the UK, miles per hour (mph). For air and marine travel the knot is commonly used.
The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum c = 299792458 metres per second (approximately 1079000000 km/h or 671000000 mph). Matter cannot quite reach the speed of light, as this would require an infinite amount of energy. In relativity physics, the concept of rapidity replaces the classical idea of speed.

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  1. O

    Slow drain toilet with old & new AAV but fine without

    Hi all, Hope you're well. Anyone any ideas... randomly 2 of our toilets started backing up when flushed (2 on same stack 1st floor and ground, 3rd loo (2nd floor) on its own seperate riser is fine) and takes circa 10s to level out. When flushed you can hear the gurgles and burps from the...
  2. C

    I have fitted flowmasta bottom fill valve. the water flow

    I have fitted flowmasta bottom fill valve. The water why flow is very slow. Anyone any ideas why
  3. P

    how do I fix the cold water faucet that is barely running?

    My upstairs cold water faucet just barely streams out.. The cold and the hot in the shower are fine but not the cold water of the sink. Is there anything I can do myself without calling for a costly pllumber?
  4. S

    Slow leak on my pressured central heating system

    Hi, new to this forum. I hope someone experienced out there can help me find the fix. We recently finished a building project and had a major re-design/move of all of our hot water (megaflo), boiler and central heating system. I am not a plumber nor do I know much about plumbing but I know...
  5. X

    slow draining toilet following pan connector replacement

    Hello All, We recently had a plumber out to replace a pan connector as the previous set up had developed a leak, however, following the replacement the toilet doesn't drain properly - the flush starts off ok, but partway through the water levels starts to rise, it then takes ages to drain, and...
  6. A

    Radiators very slow to heat up

    Radiators very slow to warm up on ground floor. I live in a two storey house with unvented hot water cylinder and closed CH system. Boiler is on ground floor. The unvented hot water cylinder, water pump and expansion vessels are in the loft. Ground floor CH has two port valve and radio...
  7. J

    My boiler hot water flow rate is slow

    Vaillant Ecotec Pro 28 Running 7 radiators. Outside Tap Cold water flow rate = 12l/s (it took 5s to fill 1l pot) Kitchen Tap - just running cold water = 4 l/s Bristan Shower Mixer - cold water rate = 12 l/s Hot water rate is really low The boiler heats up the water fine -its nice and hot...
  8. D

    Basement pipe in wall slow leak. Does it need to be cleaned out?

    Hi, I am new here and I need some help with a home repair. I have this pipe located in my basement inside my wall made of concrete that is showing signs of water leaking onto my basement floor. There is no leaks from the pipe itself, the water is only coming from the bottom where the concrete...
  9. D

    Basin slow to empty

    Having a slight problem with the basin slow emptying. Plunnging it helps a little, i have taken the trap off and its clear, the pop up waste is clear, the waste runs into the internal soil stack, i think the issue is a flat run of the waste for about 2 meteres along the floor. I did ask the...
  10. T

    Slow filling cistern, lot of air

    The cistern has been filling fine for nearly a year, then in the last week or so it has been taking ages to full. Taking thr cover off the symphonic release is working and sealing fine upon completion. The float on the fill is working, but when it's filling their is a trickle and a fine spray...
  11. L

    Bathroom sink very slow drain mystery

    The bathroom was refitted 10 years ago. Everything was fine until a couple of years ago. The basin is very slow draining and you can see the water coming up from the P trap and then filling up the basin. I've tried drain unblockers etc. and also put a hose with a snug fitting nozzle into the...
  12. R

    Hot Water Taps all running slow then stopping

    Hi, I have today removed our bath ready to put a new one in and have capped both the hot and cold feeds off. However, when putting both the hot water (turned off as cold feed on to the cyclinder) and cold water back on (turned off at both the stop tap under the sink and the cold feed in the...
  13. S

    URGENT Hi have a potterton performa 24he hot water flow is very slow. Have changed plate heat exchanger and made no difference any ideas?

    Hi have a potterton performa 24 he hot water flow is very slow. Have changed plate heat exchanger and made no difference heating is fine any ideas?
  14. B

    New Kitchen Tap - slow drip

    I bought a new kitchen mixer tap. Link below. https://www.wrenkitchens.com/aurora-tap-chrome-high-low-pressure/8901 Every time I walk into the kitchen, I see a drip on the end of the tap. I remove the drip, to discover another drip on the end of it after about couple of hours. Now, is there a...
  15. R

    Shower/ Sink very slow to drain to macerator

    I have a macerator which does a toilet, sink and shower in our basement, it has worked fine for 2 years then water started backing up into shower tray so I took the macerator out (3 hr job due to location) and the non-return valve had come a bit loose. Repaired that, gave it a good clean out...
  16. D

    Slow dry solvent cement for ABS

    Hi, does anyone know of a slow dry/cure solvent cement for ABS waste pipes please? Got some 50mm floplast ABS waste pipes in a tricky ceiling that will be a pain to get the cement on, line up and push together before the normal solvent cement goes off - in the 15 seconds you get to fit them...
  17. Jeffrey Griffin

    Kitchen hot tap flow v slow

    Hi there. Have a carron mixer tap in kitchen the flow on the hot tap side has become very slow for no apparent reason. To almost a trickle...was never like that previously. Hot tap in bathroom.upstairs is strong. When I remove the connection under the sink the flow seems good and strong but...
  18. P

    slow draining from shower tray

    hi guys and girls need a bit of advice from a plumber or that, i fitted a new low shower tray and its draining very slow i have to switch off power shower to stop water getting close to the top of tray all i changed was tray it came with its own waste trap and connected it with flex pipe as...
  19. K

    Glow Worm 38cxi slow startup

    Our Glow Worm 38cxi boiler is about 15 years old. When turning on the central heating in the morning, the boiler fires for a moment and the pump starts, then the green light goes off but the pump continues to circulate the water. The temperature of the water on the boilers digital display drops...
  20. T

    Blocking a slow leak

    I am preparing to refinish my bathtub. The tub faucet leaks one drop/second. Obviously, I can't begin spray painting with a wet tub. What can I use to block the slow leak for the 3 days it takes for 2 coats of paint to dry?