# physics

posted by .

in a certain system,the water used for storage is initially at 70 degree Celsius and it is required to provide an average of 7.5 kW to keep the house at an average of 18 degree Celsius for 3 days,how much water is needed.

• physics -

Q = Pt = mc(T2-T1)
where
Q = heat/energy (in J)
P = Power (in W)
t = time (in s)
m = mass (in kg)
c = specific heat capacity (in J/kg-K) = 4.184 J/kg-K for water
T = temperature (in C or K)
we're solving for mass. substituting,
(7.5*1000)*(3*24*60*60) = m*4.184*(70-18)
1944000000 = 217.568m
m = 8935137.5 kg = 8935.14 tons of water

## Similar Questions

1. ### Science

Calculate how much 95% ethyl alcohol will be required to dissolve 075g sulfanilamide at 78 degree Celsius. Knowing that solubility of sulfanilamide is 210 mg/ml at 78 degree Celsius, 14mg/ml at 0 Degree Celsius.
2. ### chemistry

calculate the weight of crystal formed on cooling 80 gm of saturated solution from 60 degree Celsius to 30 degree Celsius. solubility of salt at 60 degree Celsius and 30 degree Celsius are 132 and 95 respectively.
3. ### college physics

A cube of ice is taken from the freezer at -9.5 degree Celsius and placed in a 99 g aluminum calorimeter filled with 327 g of water at room temperature of 20.0 degree celsius. The final situation is observed to be all water at 17.0 …
4. ### Physics 100

A 355-g piece of metal at 48.0 degree celsius is dropped into 111g of water at 15.0 degree celsius.If the final temperature of the mixture is 32.5 degree celsius what is the specific heat of the metal?
5. ### Chemistry

What volume of 15 degree celsius water must be added to a 1.2KG piece of stainless steel at 85 degree celsius so that the final temperature is 35 degree celsius. assume the container in which the mixing takes place is perfectly insulated.
6. ### physics

A 500 g piece of silver at 150 degree Celsius is submerged in 1000 g of water at 5 degree Celsius to be cooled. determine the final temperature of silver and water given Cwater = 4.18 x 10 ^3 J/kg degree Celsius Csilver = 2.4 x 10^2 …
7. ### Physics 2

calculate the final temperature of a 400g of water at 80 degree celsius if it is poured into a 100g pot at 30 degree celsius. note: c of pot is 840 J/kg degree celsius.
8. ### physics

An insulated beaker contains 300g of water initially at 30 degree celsius. water at 100 degree celsius is added until the temperature of mixture reaches 50 degree celsius . the specific heat capacity of water is 4.2J/(kg degree celsius). …
9. ### Physics

At room temperature of 30 degree celsius, a glass of water takes one minute to cool from 80 degree celsius to 60 degree Celsius. How long will it take to further cool from 60 degree celsius to 50 degree celsius?
10. ### Chemistry

1) how many joules are required for each of the following?

More Similar Questions