Recent content by physicskillsme

Aluminium Spray paint

So this the solution? The immersion heater in an electric hot water system is rated at 9 kW. If the tank is initially filled with 40 gallons (about 150 litres, with a mass of 150 kg) of cold water at 15 oC, how long will it take the heater to raise the temperature to 40 oC? Q=CmdeltaT...

So I need to do the calcualtions for each of these steps? Yes I am having problems with solving for variables it just seems so complicated. Do you know of any good tutorials for this?

Extracted from another thread tha had got a bit messy. The immersion heater in an electric hot water system is rated at 9 kW. If the tank is initially filled with 40 gallons (about 150 litres, with a mass of 150 kg) of cold water at 15 oC, how long will it take the heater to raise the...

OK thanks for your help.

m=0.4kg deltaT 328-25= 303 SpecHeat = 128 (1) Increase the temperature to the melting point of lead. Q=mCdeltaT Q=.4*128*303 Energy Required to heat: 15513.6J (2) Melt the lead. (latent heat of fusion) L=0.25x10^5 Taken for a list of properties...

OK so I have the step 1 part OK? How do I set up part two? Latent heat (fusion) requires a separate equation presumably, I mean different to the Specific Heat in part 1? So how does this look? Heat Energy = m X L + m X c X q

Am I on the right track here? How much energy is required to melt 400 grams of lead, if the initial temperature is 25 oC? m=0.4kg deltaT 328-25= 303 SpecHeat = 128 Q=mCdeltaT Q=.4*128*303 15513.6J

Yes and your advice is not wasted on me (Likewise for other 'helpers'). Thank you for your support.

So t=p*q ?

How are the units wrong?

Ok so I need some help here..this is how I see it and what you say makes sense however my boots are stuck in the mud and I need help pulling them out. What should I be doing to get unstuck? Q=CmdeltaT deltaT=40-15 = 25 q=Q=4196*150*25 15735000J How do I go about getting this...

yep I googled and came up with Gallium as being the answer you'd give in a class although it Ceasium is worth a mention too.

Could someone check I have these setup right and check my answers - if not where have I gone wrong. How long will it take a 50 hp motor to do 1 MJ of work? 1hp=746W = 50*746=37300W 1 MJ = 1000000J / 37300W = 26.8 secs ----------------------------------------- A 650 W microwave...

There is one metallic element which is normally a solid, but which will melt if you hold it in your hand. Which element is it? Is it Francium?