physics power, temperature問題

2007-01-07 3:48 am

power 有冇分input power 同output power?即係想問如果樣野是50W, means take in 50W energy/s OR 做出50W的功/s OR 同時take in 50W 做出50W的功/s???

objects have same average kinetic energy have the same temperature, that's mean if these two objects are water and solid respectly, is also correct??

Air have the convertion current helps to 散熱, but why still 令heater damaged??而水側不會呢??

回答 (1)

用戶157649

2007-01-07 8:20 am

✔ 最佳答案

1.如果你想問果樣野係一個標示50W 的燈泡
即是這燈泡每秒會消耗 50J 的 work done 以維持規定之亮度

2.Same KE 不等於 same temp
KE = 0.5 x mass x velocity^2 即是一件 mass m 物件以速度 v 移動就持有動能KE
而溫度是指這物件所持的熱能, 跟物件的成份無關係
但如果溫度有流失/增加, 物件的heat capacity 就影響能量, 參考HEAT這一PART

3.你意思係問點解水散熱好過風散熱嗎?? 唔係請再問一次
因為水有比空氣較高的heat capacity, 參考HEAT這一PAR,T E=mc(delta T)
熱能比較容易被水帶走, 逹致冷卻的效果

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