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Posted

Hey guys,

I've just started on Power in physics and its all really cool.

We did this prac where we walked up some stairs and calculated our power.

 

One of the questions is:

 

Your local electric company supplies you 1kW of power for 1 hour for 8c.

Assume that you could climb stairs continuously for 1 hour.

How much money would this climb be worth?

 

well, the climb took me 4.22seconds and the power used for that was 332W.

 

How would I go about solving this? My maths is horrible, but luckily for me this year doesn't count towards my exit statement. So I'm working really hard to catch up :D

 

Any help at all would be great, I am trying to convert it all n stuff but its being really difficult, I would really appreciate it if you could just lend me a hand.

 

So far I've been trying to convert the 4.22 seconds into an hour and change the power so its in ratio. But I haven't been able to achieve it at all.

 

It isn't all that important, but it would be really nice if you could help me.

Thanks guys :), I'm off to try do it some more

Posted

I'm thinking along the lines of 332/4.22 (joules per second)

then /1000 for kJ.

is this correct? I'm doing a lot of fiddling. Stupid dentist drugged me :P

 

*kilowatts sorry

Posted

1000(joules)/1(second)=1000joules per second=1kj p second= 1 x 8(cents)= What I'm worth?

 

oh sorry, didn't know about Edit post thing.

 

I mean Kilowatts of course!!!

Posted

Yes, if you produced 332W in 4.22s, you are generating 78.7W, or 0.0787 kW.

 

at $.08 per hour, you still haven't made a whole penny. .63c

Posted

Cost = power (kW) x time (hours) x cost of 1kWh (kilo watt hour)

 

Well that's standard for calculating the cost of electricity, I'm sure you could use it for youself in this conext.

 

[edit] see swansont beat me!

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