标题: physics 帮帮忙 [打印本页] 作者: ymgoh95 时间: 2012-11-16 03:54 PM 标题: physics 帮帮忙 What is the final temperature when 100g of water at 25'c is mixed with 75g of water at 50'c作者: ymgoh95 时间: 2012-11-16 04:07 PM
A voltmeter reading is 1.5V when the switches opened.The voltmeter reading drops to 1.35V when a bulb is connected to the battery meter reading is 0.3A.
What is the internal resistance of the battery?.作者: warriorwj 时间: 2012-11-16 04:29 PM
我在想你在这里问会有人回答你吗？
那个internal resistance is using the V=IR formula.
the temperature is using the energy formula (energy lost = energy gain)作者: P2PSYSTEM 时间: 2012-11-16 04:44 PM 回复 1#ymgoh95
0.1 x 4200 x 25 + 0.075 x 4200 x 50= 0.175 x 4200 x T
T=35.71