Exercise Solution       Solution

1.  This is a use of the relationship that the mass is equal to the product of the density and volume.

 

3.  We find the specific gravity by taking the ratio of the density of the fluid to that of water. The same volume must be used for both liquids.

 

7a.  The pressure exerted on the floor by the leg is caused by the leg pushing down on the floor. That downward that push is the reaction of the normal force of the floor on the leg, and the normal force is equal to the weight of the leg.

Pressure = weight over divided by area

 

7b  Pressure exerted by elephant = Weight of elephant divided by area

 

Note that the chair pressure is larger. Why?

 

 

14a.  Pressure = density time g times h.  Force = Pressure times area

 

14b.  The pressure against the side near the bottom is the same as the pressure at the bottom (good assumption with the given data).  Same as above.

 

22. The difference between the actual mass and apparent mass is just the mass of the displaced water.  The mass of the water displaced can be found from the volume of the rock times the water density. The volume of the rock is the mass of the rock divided by its density. These can be combined to find the rock's density

 

22.   The difference in the actual mass and the apparent mass is the mass of the water displaced by the rock.  The mass of the water displaced is the volume of the rock times the density of water, and the volume of the rock is the mass of the rock divided by its density.  Combining these relationships yields an expression for the density of the rock.

 

35. We use the equation of continuity for an incompressible fluid.

 

(AV)aorta = (AV)arteries    solve for varteries

 

We can use Torricelli's theorem and solve for velocity

 

45.  We use Bernoulli's equation. We just assume the pressure on the outside is air pressure and the speed inside is 0. We also assume the pressures are made at the same height.