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				 作者ETM1231 
				You dive straight down into a pool of water. You hit the water with a speed of 7.0 m/s, and your mass is 70 kg. 
 
Assuming a drag force of the form Fd=(−1.40×10^4 )*v , how long does it take you to reach 2% of your original speed? (Ignore any effects of buoyancy.) 
請問這題是要用到積分嗎? 
因為下水後受到阻力, 速度變慢, 阻力變小, 速度又變慢, 阻力又變小... 
無奈目前數學工具不足, 也不知觀念是否有誤... 
煩請各位高人指點一二, 感恩... 
			
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