EV CHARGING AND FUSE

[ericmark]

The 'hour' in kWh has everything to do with time.

Sorry no, a watt is a Joule per second, so the seconds in the watt are cancelled out by the hour in the kWh, so all is left is 60 x 60 (seconds in a minute and minutes in an hour) so there are 3600 Joules in a Watt/hour or 3600 kJ in a kWh. Both measurement of energy, nothing to do with time.

 

[EFLImpudence]

I don't know how to explain it either.

How can you do 60 miles per hour if you only go out for 20 minutes?

 

[ebee]

Adding that a journey at 100mph and the same journey in reverse at 50mph does not result in an average of the whole round trip at 75mph - but not a lot of people know that.

PS - Sorry for using the word "Average" it is possibly the most dangerous word in the Universe!

 

[SUNRAY]

Adding that a journey at 100mph and the same journey in reverse at 50mph does not result in an average of the whole round trip at 75mph - but not a lot of people know that

Yep fools most

 

[bernardgreen]

3600 Joules in a Watt/hour or 3600 kJ in a kWh

would 3600 Joules in a Watt.hour be a better way to write Watt hour

 

[SUNRAY]

Adding that a journey at 100mph and the same journey in reverse at 50mph does not result in an average of the whole round trip at 75mph - but not a lot of people know that

In grandsons GCSE revision questions was 60km/h for 2 hours and the return journey at 20km/h. He was doing it on video call with a friend, they discussed at length and made it 15km/h but my grandson kept saying it has to be more than 20...

At least he questioned it and asked me jus tbefore I was about to step in. Annoyingly I think he would have been fine with it if he was on his own

 

[ebee]

my grandson kept saying it has to be more than 20...

Good lad.

Ask him this one (verbally not in text) "If a brick weighs 7 pounds and half a brick, what does a brick and a half weigh?" .

I got it as a kid but I did take a few tries though, you should have heard all the different answers other gave at our Xmas gatherings.
I bet you lad would get it.

 

[SUNRAY]

Good lad.

Ask him this one (verbally not in text) "If a brick weighs 7 pounds and half a brick, what does a brick and a half weigh?" .

I got it as a kid but I did take a few tries though, you should have heard all the different answers other gave at our Xmas gatherings.
I bet you lad would get it.

That's a kin eavy brick

 

[ebee]

That's a kin eavy brick

Around here it is not by any means uncommon for folk to use the word "brick" to include stone (usually sandstone) shaped to size and made from sandstone etc and several times bigger than common bricks but used in a broadly similar way to what you might build and use a brick for. Some might even use the term for great slabs of stone used to build the Great Pyramid which I think were mostly about 2 to 19 tons. But yes to me and thee such a brick in the question would certainly be a very heavy "brick" but for purposes of the question the figures seem to fit neatly to a sort of "conundrum" in folks minds. I dont think Kg would have quite the same appeal, whether thru a weight conversion or purely keeping the numerical value. The important thing (I think) is to ask it as a spoken question not written and preferably asked only once or exceptionally no more than twice. I certainly generates a few heated words, even after the answer is revealed.

Back in the days before computers and TV was in relative infancy I suppose, family gatherings such as Xmas and these simple games and quizzes could provide hours of fun.
In my case it was my Grandad that collected most of them probably handed down from the generations before him and then a few more added by people who had attended other gatherings as well.
Nowadays its folks with buttons on ipads and iphones who constantly wander around like "Smart Phone Zombies"

 

[SUNRAY]

Around here it is not by any means uncommon for folk to use the word "brick" to include stone (usually sandstone) shaped to size and made from sandstone etc and several times bigger than common bricks but used in a broadly similar way to what you might build and use a brick for. Some might even use the term for great slabs of stone used to build the Great Pyramid which I think were mostly about 2 to 19 tons. But yes to me and thee such a brick in the question would certainly be a very heavy "brick" but for purposes of the question the figures seem to fit neatly to a sort of "conundrum" in folks minds. I dont think Kg would have quite the same appeal, whether thru a weight conversion or purely keeping the numerical value. The important thing (I think) is to ask it as a spoken question not written and preferably asked only once or exceptionally no more than twice. I certainly generates a few heated words, even after the answer is revealed.

Back in the days before computers and TV was in relative infancy I suppose, family gatherings such as Xmas and these simple games and quizzes could provide hours of fun.
In my case it was my Grandad that collected most of them probably handed down from the generations before him and then a few more added by people who had attended other gatherings as well.
Nowadays its folks with buttons on ipads and iphones who constantly wander around like "Smart Phone Zombies"

I'm assuming (always a silly thing to do) the answer is 21lb but I can read it in different ways as 10½, 11¼ or using algebra I got to 15¾ but can't work out how my scribble got there or get there again.

 

[EFLImpudence]

"If a brick weighs 7 pounds and half a brick, what does a brick and a half weigh?" .

15¾lb.

 

[SUNRAY]

15¾lb.

Yeah I got to that once but can't work out again how but I think it's wrong.

 

[EFLImpudence]

Yeah I got to that once but can't work out again how but I think it's wrong.

Me too. Very strange.

I make it 21 now.

 

[morqthana]

Sorry no, a watt is a Joule per second, so the seconds in the watt are cancelled out by the hour in the kWh, so all is left is 60 x 60 (seconds in a minute and minutes in an hour) so there are 3600 Joules in a Watt/hour or 3600 kJ in a kWh. Both measurement of energy, nothing to do with time.

I scarcely know where to begin....

A joule is a unit of energy. It's equal to the amount of energy dissipated as heat when 1 amp flows through a 1 ohm resistor for 1 second.

A watt is a unit of power - it measures the rate of energy transfer and 1 watt is the measure of transferring 1 joule per second.

A watt-hour is also a unit of energy, just like a joule. It's the energy delivered by 1 watt of power for 1 hour. 1Wh = 3600J

Joules and watts have different dimensions. Joules and watt-hours have the same dimensions, because the watts have been multiplied by time.

The 'hour' in kWh has everything to do with time.

 

[morqthana]

Using AU to describe the distance to the sun but not to the shops.

Unless what matters at the time of use is to say how many multiples of the distance to the sun an object is from us, it's a pretty poor indication of actual distance.

1au is approximately 0.15Tm

A light-year is approximately 9.5Pm

The most distant known galaxy is in the yottametre range, and there's still two more SI prefixes to go. We could just use metres for everything.