What fraction of the interior volume is filled with water when the car sinks?

By admin | May 23, 2009
interior
Natiphy2007 asked:


Advertisements for a certain, small car claim that it floats in water.If the car’s mass is 880kg , and its interior volume is 3.3 m^3, what fraction of the car is immersed when it floats? You can ignore the volume of steel and other materials.
Express your answer using two significant figures.
B) Water gradually leaks in and displaces the air in the car. What fraction of the interior volume is filled with water when the car sinks?
Express your answer using two significant figures.

Kansieo.com
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2 Comments so far
  1. Prashant May 25, 2009 10:47 am

    Use Archimedes’ Principle :

    Buoyant force = Weight of water displaced
    Weight of car = Volume immersed x Density of water x g

    In the second part, Buoyant force should be equal to Weight of car + Weight of water inside the car

    Try solving it further.

    If you have any problem, you may mail me at

  2. ukmudgal May 25, 2009 7:06 pm

    _______________________________–

    We ignore the volume of steel and other materials.

    Volume of car = V =3.3 m^3

    Mass of car = m =880 kg

    weight of car = 880*g N

    Let the volume of displaced water = v

    weight of displaced water = v*d*g=1000v*g N

    For floatation of car,

    weight of displaced water = weight of car

    1000vg=880g

    v =880/1000 =0.88 m^3

    Fraction of volume immersed = v/ V =0.88/3.3= 88 /330 =0.27

    fraction 0.27 of the car is immersed when it floats
    _____________________________
    Edited.
    B ) The car will sink when weight of car plus weight of water inside weighs more than weight of water displaced by the complete car inside water

    Volume of water = v

    Weight of water inside car= w1 =vdg=1000vg

    Weight of the car (without water) = w2 =880g

    weight of water displaced by the complete car inside water= W= Vdg=3.3*1000*g=3300g

    w1 + w2 = W

    1000vg + 880g = 3300g

    1000v=2420

    v=2.42 m^3

    v / V =2.42/3.3=0.7333

    The fraction of the interior volume when the car sinks is 0.7333

    _________________________

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