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Updated Mar 14, 2026
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Delo, Energija in Moč v Fiziki
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Osnovni pregled in ključne definicije
Delo (A) je tisto, kar narediš, ko s silo premaknеš neki predmet. Ampak pozor - sila mora delovati v smeri gibanja! Če nosiš nahrbtnik vodoravno po hodniku, tvoje roke ne opravljajo dela, čeprav se utrudiš.
Energija (E) je kot baterija v telefonu - pove ti, koliko "moči" imaš za opravljanje dela. Obstaja v različnih oblikah: energija gibanja, energija višine, toplotna energija in še druge.
Moč (P) pa je hitrost opravljanja dela. Predstavljaj si jo kot razliko med polnjenjem telefona z običajnim polnilcem ali s hitrim polnilcem - delo je isto, ampak čas je drugačen.
💡 Pomni: Vse tri količine merimo v povezanih enotah - delo in energijo v joulih (J), moč pa v wattih .
Delo - ko sila premakne predmet
Formula za delo je preprosta: A = F × s. To pomeni sila krat pot. Ampak pazi na tri situacije, ko delo ni opravljeno!
Prvo, ko sila ne deluje v smeri gibanja. Če potiskaš voziček naprej, a pritiskaš navzdol, samo del tvoje sile opravlja delo. Drugo, ko se predmet sploh ne premakne - lahko se potrudiš pri potiskanju stene, ampak ker se ne premakne, je delo nič.
Tretje, ko ni sile v smeri gibanja. Ko hodiš po ravni cesti s konstantno hitrostjo, na tebe deluje le sila teže navzdol in normalna sila navzgor - nobena v smeri hoje.
Kinetična energija je energija gibanja. Vsak gibljivi predmet jo ima. Formula je Ek = ½mv² - pozor na kvadrat pri hitrosti! Če se hitrost podvoji, se energija poveča štirikrat.
💡 Pomembno: Enota za delo je joule (J) = newton × meter. En joule je malo energije - približno toliko, kolikor rabiš za dviganje jabolka za en meter.
Potencialna energija in ohranitev energije
Potencialna energija je "shranjena" energija zaradi višine. Kamen na vrhu stolpa ima potencialno energijo, ker lahko pade in pri tem opravlja delo. Formula je Ep = mgh.
Tukaj je ključen zakon o ohranitvi mehanske energije. Če ni trenja, se skupna energija ne spreminja - samo preoblikuje se iz ene v drugo.
Ko žoga pade z balkona, se njena potencialna energija zmanjšuje (ker pada), kinetična pa povečuje (ker pospešuje). Tik pred tlemi je vsa začetna potencialna energija postala kinetična.
Ta zakon ti omogoča elegantno reševanje nalog - ne rabiš računati vmesnih korakov, ampak samo primerjaš začetno in končno stanje sistema.
💡 Praktičen nasvet: Pri nalogah z ohranitvijo energije postavi enačbo Ek,začetna + Ep,začetna = Ek,končna + Ep,končna in rešuj neznano količino.
Moč - hitrost opravljanja dela
Moč pove, kako hitro opravlјaš delo. Formula je P = A/t - delo deljeno s časom. Če dva učenca dvigneta isto škatlo na isto višino, opravita enako delo. Če pa eden to naredi v pol časa, ima dvakrat večjo moč.
To je razlika med običajnim in športnim avtomobilom. Oba lahko pripeljeta iz Ljubljane v Maribor (enako "delo"), ampak športni to naredi hitreje (večja moč).
| Količina | Enota | Formula |
|---|---|---|
| Delo | Joule (J) | A = F × s |
| Energija | Joule (J) | Ek = ½mv², Ep = mgh |
| Moč | Watt (W) | P = A/t |
Watt je joule na sekundo. Običajna žarnica porabi okoli 10 W, mikrovalovna pa 1000 W = 1 kW.
💡 Za teste: Pri nalogah najprej preveri enote! Masa v kg, pot v m, čas v s. Če so podane drugače, jih pretvori.
Rešeni primeri za boljše razumevanje
Primer z delom: Janez potiska 50 kg zaboj s silo 100 N za 5 m. Opravljeno delo = F × s = 100 N × 5 m = 500 J. Masa je odveč podatek!
Primer z energijo: 2 kg kamen pade z 10 m višine. Začetna potencialna energija = mgh = 2 × 10 × 10 = 200 J. Po zakonu ohranitve bo tik pred tlemi vsa ta energija postala kinetična = 200 J.
Primer z močjo: Dvigalo dvigne 500 kg tovora za 20 m v 10 s. Najprej delo: A = F × h = (mg) × h = 5000 N × 20 m = 100.000 J. Nato moč: P = A/t = 100.000 J / 10 s = 10.000 W = 10 kW.
Opazi vzorec - vedno najprej zbereš podatke, potem izbereš formulo, nato računaš in na koncu preveriš, če je rezultat smiseln.
💡 Preverjanje: 10 kW za dvigalo je realna moč - približno kot 10 mikrovalovk, ki delujejo hkrati.
Pomembni nasveti in povzetek
Pazi na pogeste napake! Delo v fiziki ni isto kot vsakdanji napor - držanje težke uteži pri miru ne pomeni opravljanja dela, čeprav se mišice utrudijo. Delo je samo ob premiku.
Smer sile je ključna - samo komponenta sile v smeri gibanja opravlja delo. Enote moraš vedno preveriti - masa v kg, razdalje v m, čas v s.
Ohranitev energije je tvoj najboljši prijatelj pri reševanju nalog. Ne rabiš računati vseh vmesnih korakov - samo primerjaš začetno in končno stanje.
Povzetek za teste:
- Delo: Sila premakne predmet. A = F × s
- Kinetična energija: Energija gibanja. Ek = ½mv²
- Potencialna energija: Energija višine. Ep = mgh
- Moč: Hitrost dela. P = A/t
- Ohranitev: Ek + Ep = konstanta (brez trenja)
💡 Za uspeh: Te koncepte boš potreboval pri vseh nadaljnjih temah fizike - od nihanja do elektrike. Dobro jih utrdi že zdaj!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content in Naravoslovje
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5
App Store
4.7/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Delo, Energija in Moč v Fiziki
Delo, energija in moč so tri super povezani fizikalni pojmi, ki jih srečaš povsod - od dviganja nahrbtnika do delovanja tvojega telefona. Energija je zmožnost, da nekaj narediš, delo je proces, kako to narediš, moč pa pove, kako hitro to... Show more
Osnovni pregled in ključne definicije
Delo (A) je tisto, kar narediš, ko s silo premaknеš neki predmet. Ampak pozor - sila mora delovati v smeri gibanja! Če nosiš nahrbtnik vodoravno po hodniku, tvoje roke ne opravljajo dela, čeprav se utrudiš.
Energija (E) je kot baterija v telefonu - pove ti, koliko "moči" imaš za opravljanje dela. Obstaja v različnih oblikah: energija gibanja, energija višine, toplotna energija in še druge.
Moč (P) pa je hitrost opravljanja dela. Predstavljaj si jo kot razliko med polnjenjem telefona z običajnim polnilcem ali s hitrim polnilcem - delo je isto, ampak čas je drugačen.
💡 Pomni: Vse tri količine merimo v povezanih enotah - delo in energijo v joulih (J), moč pa v wattih .
Sign up to see the contentIt's free!
Access to all documents
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Delo - ko sila premakne predmet
Formula za delo je preprosta: A = F × s. To pomeni sila krat pot. Ampak pazi na tri situacije, ko delo ni opravljeno!
Prvo, ko sila ne deluje v smeri gibanja. Če potiskaš voziček naprej, a pritiskaš navzdol, samo del tvoje sile opravlja delo. Drugo, ko se predmet sploh ne premakne - lahko se potrudiš pri potiskanju stene, ampak ker se ne premakne, je delo nič.
Tretje, ko ni sile v smeri gibanja. Ko hodiš po ravni cesti s konstantno hitrostjo, na tebe deluje le sila teže navzdol in normalna sila navzgor - nobena v smeri hoje.
Kinetična energija je energija gibanja. Vsak gibljivi predmet jo ima. Formula je Ek = ½mv² - pozor na kvadrat pri hitrosti! Če se hitrost podvoji, se energija poveča štirikrat.
💡 Pomembno: Enota za delo je joule (J) = newton × meter. En joule je malo energije - približno toliko, kolikor rabiš za dviganje jabolka za en meter.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Potencialna energija in ohranitev energije
Potencialna energija je "shranjena" energija zaradi višine. Kamen na vrhu stolpa ima potencialno energijo, ker lahko pade in pri tem opravlja delo. Formula je Ep = mgh.
Tukaj je ključen zakon o ohranitvi mehanske energije. Če ni trenja, se skupna energija ne spreminja - samo preoblikuje se iz ene v drugo.
Ko žoga pade z balkona, se njena potencialna energija zmanjšuje (ker pada), kinetična pa povečuje (ker pospešuje). Tik pred tlemi je vsa začetna potencialna energija postala kinetična.
Ta zakon ti omogoča elegantno reševanje nalog - ne rabiš računati vmesnih korakov, ampak samo primerjaš začetno in končno stanje sistema.
💡 Praktičen nasvet: Pri nalogah z ohranitvijo energije postavi enačbo Ek,začetna + Ep,začetna = Ek,končna + Ep,končna in rešuj neznano količino.
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Moč - hitrost opravljanja dela
Moč pove, kako hitro opravlјaš delo. Formula je P = A/t - delo deljeno s časom. Če dva učenca dvigneta isto škatlo na isto višino, opravita enako delo. Če pa eden to naredi v pol časa, ima dvakrat večjo moč.
To je razlika med običajnim in športnim avtomobilom. Oba lahko pripeljeta iz Ljubljane v Maribor (enako "delo"), ampak športni to naredi hitreje (večja moč).
| Količina | Enota | Formula |
|---|---|---|
| Delo | Joule (J) | A = F × s |
| Energija | Joule (J) | Ek = ½mv², Ep = mgh |
| Moč | Watt (W) | P = A/t |
Watt je joule na sekundo. Običajna žarnica porabi okoli 10 W, mikrovalovna pa 1000 W = 1 kW.
💡 Za teste: Pri nalogah najprej preveri enote! Masa v kg, pot v m, čas v s. Če so podane drugače, jih pretvori.
Sign up to see the contentIt's free!
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Improve your grades
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Rešeni primeri za boljše razumevanje
Primer z delom: Janez potiska 50 kg zaboj s silo 100 N za 5 m. Opravljeno delo = F × s = 100 N × 5 m = 500 J. Masa je odveč podatek!
Primer z energijo: 2 kg kamen pade z 10 m višine. Začetna potencialna energija = mgh = 2 × 10 × 10 = 200 J. Po zakonu ohranitve bo tik pred tlemi vsa ta energija postala kinetična = 200 J.
Primer z močjo: Dvigalo dvigne 500 kg tovora za 20 m v 10 s. Najprej delo: A = F × h = (mg) × h = 5000 N × 20 m = 100.000 J. Nato moč: P = A/t = 100.000 J / 10 s = 10.000 W = 10 kW.
Opazi vzorec - vedno najprej zbereš podatke, potem izbereš formulo, nato računaš in na koncu preveriš, če je rezultat smiseln.
💡 Preverjanje: 10 kW za dvigalo je realna moč - približno kot 10 mikrovalovk, ki delujejo hkrati.
Sign up to see the contentIt's free!
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Pomembni nasveti in povzetek
Pazi na pogeste napake! Delo v fiziki ni isto kot vsakdanji napor - držanje težke uteži pri miru ne pomeni opravljanja dela, čeprav se mišice utrudijo. Delo je samo ob premiku.
Smer sile je ključna - samo komponenta sile v smeri gibanja opravlja delo. Enote moraš vedno preveriti - masa v kg, razdalje v m, čas v s.
Ohranitev energije je tvoj najboljši prijatelj pri reševanju nalog. Ne rabiš računati vseh vmesnih korakov - samo primerjaš začetno in končno stanje.
Povzetek za teste:
- Delo: Sila premakne predmet. A = F × s
- Kinetična energija: Energija gibanja. Ek = ½mv²
- Potencialna energija: Energija višine. Ep = mgh
- Moč: Hitrost dela. P = A/t
- Ohranitev: Ek + Ep = konstanta (brez trenja)
💡 Za uspeh: Te koncepte boš potreboval pri vseh nadaljnjih temah fizike - od nihanja do elektrike. Dobro jih utrdi že zdaj!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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4.6/5
App Store
4.7/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user