Register to reply 
Volume of water displaced...? 
Share this thread: 
#1
Apr908, 05:34 PM

P: 15

1. The problem statement, all variables and given/known data
Original Question  A fishing boat displaces 3.31×10e3 kg of liquid when floating in fresh water (ρ=1000 kg/m3). If salt water has a density of 1.05×10e3 kg/m^3, how many kilograms of water would the boat displace if it were floating in salt water? ==> answer is 3.31e3 kg My Question  By what amount would the volume of water displaced by the boat change? 3. The attempt at a solution Not sure what I'm doing wrong... d= m/v v= m/d vsalt= 3.31e4 kg/1050 kg/m^3 ~ 3.152 L voriginal = 3.31e4 kg/1000 kg/m^3 = 3.31 L Change in volume = 3.31L  3.152 L ~0.158 L 


#2
Apr908, 06:01 PM

Sci Advisor
HW Helper
Thanks
P: 25,251

Look at those units which you intelligently included. The volumes aren't coming out in L. They are coming out in m^3. What's the relation between the two?



#3
Apr908, 06:06 PM

P: 55

The procedure is correct, but you've made a confusion with units.
The boat displaces 3310 kg of water (either fresh or salt). Density of fresh water is 1000 kg/m3, so the volume displaced is 3310/1000 = 3.31 m3 (or 3310 litres) In case of salt water it's 3310/1050 = 3.152 m3 (3152 litres) The difference is 0.158 m3 or 158 litres. 


#4
Apr908, 06:07 PM

P: 15

Volume of water displaced...?
I actually tried 158 L just as a guess and it was still wrong...
Is that what you meant? 1 m^3 = 1000 L .158 m^3 = 158 L 


#5
Apr908, 06:31 PM

P: 55

For example, you have mass of water displaced in kg, and the density in kg/m3. So the result will be in (kg)/(kg/m3) = m3. Once you have the result in m3, you can apply the conversions you wrote, which are correct. If you're telling me that 158 litres is not a correct result, then I don't know where is the problem. Are the two boats on the same planet? 


#6
Apr1008, 05:50 AM

P: 55




Register to reply 
Related Discussions  
What does mass, volume and density of displaced water mean?  Introductory Physics Homework  4  
Volume of water in a pond HELP  Calculus & Beyond Homework  2  
Is volume displaced by an item in water = volume of item * specific gravity of item?  Introductory Physics Homework  7  
Homework help! Volume in water  Introductory Physics Homework  9  
Volume in water problem  Introductory Physics Homework  1 