三道简单的物理题~高分答谢!~
三道英文物理题,我会简单翻译一下,最好有计算过程,谢谢!
1. Will burns a 0.7 g nut beneath 56 g of water, which increases in temperature from 22° C to 50° C.
（a)Assuming 35% efficiency.what is the food value in calories of the nut? ( ）cal
(b)What is the food value in calories per gram?()calories/g
把56g的水和0.7克的坚果（坚果在水里）煮熟需要把温度从22度提升到50度.a问假设热效能是35%,坚果是多少cal,b问坚果一克多少卡路里
2. In a 25°C room, hot coffee in a vacuum flask cools from 73°C to 45°C in eight hours. What will its temperature be after another eight hours?
室温25度,一杯热咖啡从73度降到45度用了8个小时,问再过8个小时这杯咖啡是多少度
3.At a certain location, the solar power per unit area reaching the Earth's surface is 175 W/m2, averaged over a 24 hour day. If you live in a house whose average power requirement is 3 kW and you can convert solar power to electric power with 8 percent efficiency, how large a collector area will you need to meet all your household energy requirements from solar energy?
假如你的家需要的平均功率是3kw,太阳能照到地球表面的功率是175w每平方米,太阳能8%的效能是所需电能,问你需要多大面积的来接收太阳能才能达到所需的3kw
第三题答对了。第一题第二题不对。。。。