speed

In everyday use and in kinematics, the speed (commonly referred to as v) of an object is the magnitude of the change of its position over 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 is the magnitude of velocity (a vector), which indicates additionally the direction of motion.
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 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. R

    Charging speed variation

    Morning all, When I charge at home with my Indra charger, I don’t always get 7kW speed, which is frustrating when (like today) I need a full charge and it has only added about 10% overnight. I’ve got screenshots from my previous two charges and to clarify - I do nothing differently in terms of...
  2. A

    Optimum speed to improve range on MG5 LR pre-facelift

    Apologies if this is a silly question, but is there an optimum speed to aim to drive at to keep the battery as charged up as much as possible between chargers on a long journey on motorways/ A roads. I realise at 60mph you use less battery than 69mph but would driving at 50 ( if safe) help. I...
  3. P

    Speed display

    Hi all How do I get the middle display to revert back to mph if I inadvertently flick the ACC stick?
  4. Y

    Is the Speed Limit controlled when battery is low?

    I am a new MG4 XPower owner, and apart form a few minor issues it’s been very reliable! I was returning home tonight on 5% battery and suddenly the car braked sharply and wouldn’t allow me to drive above 40 mph…. I was doing 50 at the time and it certainly surprised me…. No speed limiter was...
  5. N

    Problem using the Speed Limiter

    Hi all, I have a 2022 ZSEV Trophy LR I have never used the Speed Limiter. However a run-in with a gentleman in uniform carrying a speed gun and the introduction of the widespread 20mph limit here in Wales has caused me to investigate. So, I enabled the Speed Limiter in the menu system, then...
  6. C

    Fastest Charging Speed You’ve Seen / Got?

    I know some people & reviewers have said that their 4 has struggled to hit the bigger numbers, what’s the max you’ve seen? This is mine currently taken a few mins ago at Tesla Supercharger. It was climbing but someone’s plugged in next to me and that halted that 😅
  7. J

    Low Speed charging rate variable

    I have a 7kW wall charger. Sometimes when I plug in my MG4 LR it charges at 6.8kW but other times it chooses 3.3kW. It seems quite random. Once it has decided on the lower rate no amount of plugging in / out / restarting the charger etc. will change its decision. On the dash it is set to...
  8. robert9962

    Precondition fan speed issue

    Hi all, When I preheat my car in the morning the fan speed is on low. I've tried setting the fan speed high before getting out of the car but that doesn't work. I can't see an option in the app to increase the speed either. Does anyone know how to have the fan speed higher when pre heating...
  9. A

    Is the defogger really that bad?

    It's that time of year when the windscreen is misted up in the morning so I put the demister on to clear it. My fan is usually set to 22C with auto and I only do it to clear the screen when it happens and turn it off when the screen is clear. But I notice that my power consumption ROCKETS to...
  10. A

    Charging speed

    My MG5 LR is only charging at 3kW instead of 7kW from my wall charger. It is as slow as the 13 amp granny charger. Wall charging is set to 32 amp. Any ideas anyone what wrong or where is the fault. I expect car to charge to 80% in about 8 hrs but it’s taking about 16/18 hrs.
  11. E

    MG4 power %?

    Hi All, The MG4 reports the motor power being used in % and I think this is actually motor torque since it reaches 100% almost immediately at low speed which would imply massively more torque than the motor is rated for. All thoughts? Thanks Simon
  12. ncdlloyd

    Lack of Power and Speed on Fast Roads

    I’ve read about half of the 50 or so pages of bowfer’s speed problems and I think we’re experiencing the same thing in an SE SR 23 plate. Typically we don’t take the car on fast roads, it’s mainly used for a daily short commutes on local roads. I’ve noticed behaviour where power drops off at 55...
  13. halogen

    19% soc charging speed SR

    Went to 180kw charger station... Disappointed as I only get up to 87kwh charging speed... Dammit mg stop giving false advertising
  14. J

    Xpower as a hot hatch

    Don't know about you but I couldn't give a monkey's about where this particularly sterile debate ends up. It is or isn't a hot hatch depending on your chosen definition. That's all. And if the essence of a hot hatch is that it corners well at speed, fine but my question is then: how much time...
  15. Moog42

    Speed signage indicator on dashboard

    On the back of the 20mph change in Wales where border against, has anyone ever had an update on the speed indicator on the dash? It's been flashing incorrectly for 2 years for national speed limit on motorways and trunk roads as it seems to think they are 60mph! Haven't yet driven across the...
  16. halogen

    Granny lead charging speed

    Hello. Just took delivery of my new mg4ev magnify here in Indonesia. It's a weird combination of 51kwh battery with trophy spec ... Anyways. Was charging the first time. I'm curious why am I getting 1.3kwh instead of 2kwh. While my amp meter was showing 8.7amp drawn... should it be close to...
  17. Y

    Reversing speed bug?

    Not sure if I'm doing something wrong of if there is a bug in the way the car responds in a certain situation that should be reported. Would be greatful if someone could (safely) try and replicate the following for a UK mk2 trophy. Most of the time when I put the car into reverse from a parked...
  18. Expat Ever

    Charging Speed at 10%?

    Today I inadvertently ran the main battery down lower than usual and just now plugged it into our MG wall charger when I got home. The charger reliably provides 7.2Kw when topping up in my usual range of 25 - 75%, but with the battery at 10% it was only working at 2watts. The charging port...
  19. founny1

    It doesn't do 99!

    Phase 2 Trophy LR didn't do the speed we are/were told it does. 😉
  20. M

    Cruise control unable to maintain speed

    Majority of our motorways are not flat, having slight bumps or inclines/declines. Our 2 month old ZS struggles on these, with a constant increase in power and immediately, decrease in power before repeating this process over and over. Feels your on a boat riding the waves. On the same roads, our...
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