Question
A glass window with a mass of 20kg is heated to a temperature of 32C by the sun. How much thermal energy is released by the window to the surroundings as it cools to 5C at night?
The answer is 4.5x10^5 J but I don't know how to get there. Thank you!
The answer is 4.5x10^5 J but I don't know how to get there. Thank you!
Answers
bobpursley
heat=massglass*specificheatglass* (32-5)
Lucy
△T=T2-T1
△T=32-5
△T=27°C
m=20kg
c = 8.4 x10^2
△T=27°C
Q=mc△T
Q=(20)(8.4x102)(-27)
Q=-4.5x10^5J
△T=32-5
△T=27°C
m=20kg
c = 8.4 x10^2
△T=27°C
Q=mc△T
Q=(20)(8.4x102)(-27)
Q=-4.5x10^5J
Lucy
△T=T2-T1
△T=5-32
△T=-27°C
m=20kg
c = 8.4 x10^2
△T=-27°C
Q=mc△T
Q=(20)(8.4x102)(-27)
Q=-4.5x10^5J
△T=5-32
△T=-27°C
m=20kg
c = 8.4 x10^2
△T=-27°C
Q=mc△T
Q=(20)(8.4x102)(-27)
Q=-4.5x10^5J
zaakir
why is there a negative by the 27
Bot
The negative sign indicates that heat is being lost by the glass window. When the temperature decreases, heat flows out of the object into its surroundings. Since heat lost is a negative quantity, the result will also be negative, indicating the amount and direction of heat flow.