Water at 15°C is pumped through through a car engine at a rate of 1 litre per second (1 kg per second).
when the water comes out of the engine. it is at 95°C. The engine is made of steel and has a mass if 200kg.
Specific heat capacity of water = 4200 J kg^-1 °C^-1
Specific heat capacity of steel = 450 J kg^-1 °C^-1
(a) How much energy is removed from the engine each second ?
(b) How long would it take for the engine to overheat from 15°C to 200°C if the cooling system failed ?
f.3 physics ! 1 question ! HURRY! ten points!
2008-11-10 6:13 am
回答 (1)
2008-11-10 9:20 am
✔ 最佳答案
(a)Energy removed from the engine per second
= Energy absorbed by water per second
= mc∆T
= 1 x 4200 x (95 - 15)
= 3.36 x 105 J
=====
(b)
Energy required to heat the engine from 15oC to 200oC
= mc∆T
= 200 x 450 x (200 - 15)
= 1.665 x 107 J
Time required to heat the engine from 15oC to 200oC
= (1.665 x 107)/(3.36 x 105)
= 49.6 s
=
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