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lilai3
 one year ago
WILL REWARD MEDAL/ FAN!!((((:
The fuel value of peanuts is 25 kj/ gram. If an average adult needs 2800 kilocalories of energy a day, what mass of peanuts would meet an average adult's energy needs for the day? Assume all of the fuel value of the peanuts can be converted to useful energy.
lilai3
 one year ago
WILL REWARD MEDAL/ FAN!!((((: The fuel value of peanuts is 25 kj/ gram. If an average adult needs 2800 kilocalories of energy a day, what mass of peanuts would meet an average adult's energy needs for the day? Assume all of the fuel value of the peanuts can be converted to useful energy.

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UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.11 adult's energy requirement = 2800 kc/day how many kilo calories are required "for the day"?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1how many joules of energy, is 1 kilocalorie?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1so how many joule of energy is 2800 kilocalories, i.e. 2800 [kc] x 4.184 [j/kc] =

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1So , we have a requirement of 11715.2 [ j ] . And, we know the fuel value of peanuts is 25 [ kj / g ]

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1wait a minute 4.184 kilojoules* of energy, is 1 kilocalorie!

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1so we have 11715.2 [kj ] .

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0yeah. how do you set it up?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1food value [ kj/g ] = energy [ kj ] / mass [ g ] so mass [ g ] = energy [ kj ] / food value [ kj/g ]

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0oh and then you just divide it and the answer will be in grams?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1yeah , what do you get?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1doe it seem like a reasonable result?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1mass of peanuts [g] = 11715.2 [kj ] / 25 [kj/g]

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1the energy required is the 11715.2 [kj]

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0that feels more correct than the answer I got less than 1 last time

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1yeah, about half a kilo seems reasonable to me

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0so basically we just had to convert kilocalories to kilojoules to get the mass?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1first, we found the energy required in the time considered (one day) then we converted the energy from kilocalories to kilojoules and then from kilojoules, we used the fuel value of peanuts to find the mass of peanuts that provides this energy

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0Oh, okay. I see how it relates to the problem now. Thanks.

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0I have one more if you don't mind.

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0The specific heat of aluminum is 0.902 joule / g x Celsius and that of silver is 0.235 joules / grams x Celsius. You have two spoons of equal masses. One is made of aluminum and other silver. Which spoons would increase in temperature faster in a pot of hot soup? Why?

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0Do you think you can help me with this one?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1if we look at the units of specific heat capacity, that is \([\frac{\textrm j}{\text g\,°\text C}]\)

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1the units say the specific heat capacity is: the energy [joules] to heat a mass [grams] by a temperature [°C]

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0yeah, i understand that.

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1so which spoon takes the lesser amount energy transfer to heat up

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0Would it be the silver? Since 0.235 is less than 0.902 joules? So then it would take less amount for energy to heat?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1yep, from experience, we know that metals are good conductors of heat [ metals feel very cold on a normal day, or burn us quickly if they are hot and we touch them ]

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1silver is a 'better' metal than aluminium more shiny and much better conductor

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0so the aluminum will be faster to heat up in a pot of hot soup because 0.902 joules is greater than 0.235 joules.

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1nope the Al takes more energy to transfer temperature

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1(which takes more time)

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0wait so the higher the joule, the more energy it requires for it to heat something up?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1more to heat it up AND more to cool it down

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0so silver will increase the temperature faster due to it's smaller joule, which makes the process of heating faster than the alumiunum?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1the mass are the same , the comparison is the joule to degree ratio

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0So my answer is going to be The silver spoon will increase in temperature faster than aluminum since silver has a smaller joule. The higher the number of joules, the more energy it requires to heat up something.

lilai3
 one year ago
Best ResponseYou've already chosen the best response.0is it okay? should i add anything?

UnkleRhaukus
 one year ago
Best ResponseYou've already chosen the best response.1The silver spoon will increase in temperature faster than aluminium spoon, since the masses are the same, and silver has a smaller specific heat than aluminium: The greater the specific heat, the more joules of energy must transfer to the spoon; the more time is required for soup to heat the spoon by a given amount.
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