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# GCSE OCR Physics equations help watch

1. I'm absolutely okay with remembering stuff about Physics but when it comes to energy transferred, power, time, kilowatts and cost of kilowatts I get stumped. I really have and after quite a bit of revision on kilowatts etc still don't understand how to solve certain exam questions involving converting kilojoules and kilo watts, I just suck!! Is there a video that explains this or anyone that can? Thanks
2. (Original post by Clearist)
I'm absolutely okay with remembering stuff about Physics but when it comes to energy transferred, power, time, kilowatts and cost of kilowatts I get stumped. I really have and after quite a bit of revision on kilowatts etc still don't understand how to solve certain exam questions involving converting kilojoules and kilo watts, I just suck!! Is there a video that explains this or anyone that can? Thanks
Welcome. Post some examples of the questions you struggle with together with an explanation of where you are having difficulty. We can take it from there.
3. I don't have a question sheet with me RN but ones using the formula cost = number of kWh x cost per kWh and energy transferred (in kilo-watt hours) = power (kilo-watts) x time (in hours). I just really don't understand when they ask you a question and you need to convert the 1kw = 1000kwh? I have no idea
4. 1000W = 1KW
1KWh = 1KW x 1 hour
1KWh means in one hour, one kilowatts of energy has been transferred.
2KWh means in one hour, two kilowatts of energy has been transferred, I think.

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5. (Original post by Junaidc122)
1000W = 1KW
1KWh = 1KW x 1 hour
Correct

(Original post by Junaidc122)
1KWh means in one hour, one kilowatts of energy has been transferred.
2KWh means in one hour, two kilowatts of energy has been transferred, I think.
Not quite. Your units are slightly off:

kWh means, one kilo joules of energy has been transferred every second for one hour.

Power = watts

Energy = joules

Power = Energy / Time

1 watt of power = 1 joule of energy transferred in 1 second

therefore:

1kW = 1000 watts = 1000 joules per second

1kWh = energy transferred in 1 hour

i.e.

1kW x 1 hour = 1000 joules/second x (60 x 60) = 1000 x 3600 = 3.6 x 106 joules transferred in 1 hour.

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