physic(急!!)－wszspj2的部落格

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physic(急!!)

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A drill is used to bore a small hole in a block of iron with a mass of 75g.The temperature of the block increase from 30℃ to 52℃ after drillng.(Given:specific heat capacity of iron=470J kg-1 ℃-1)a).How much bnbrgy is supplied to the bock during the drilling?b).If this amount of energy is used to heat the same... 顯示更多 A drill is used to bore a small hole in a block of iron with a mass of 75g.The temperature of the block increase from 30℃ to 52℃ after drillng.(Given:specific heat capacity of iron=470J kg-1 ℃-1) a).How much bnbrgy is supplied to the bock during the drilling? b).If this amount of energy is used to heat the same amount of water at 30℃,what will the final temperature be?(Given:specific heat capacity of water=4200J kg-1 ℃-1) THX!!10MARKS!!

最佳解答:

A drill is used to bore a small hole in a block of iron with a mass of 75g.The temperature of the block increase from 30℃ to 52℃ after drillng.(Given:speci fic heat capacity of iron=470J kg-1 ℃-1) a).How much energy is supplied to the bock during the drilling? E = mcΔT = 0.075 x 470 x (52-30) = 775.5J b).If this amount of energy is used to heat the same amount of water at 30℃,what will the final temperature be?(Given:specific heat capacity of water=4200J kg-1℃-1) E = m水c水ΔT水 775.5 = 0.075 x 4200 x ΔT水 ΔT水 = 2.46℃ 所以溫度為 30 +ΔT水 = 30 + 2.46 = 32.46℃

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