PhysicsLAB Practice Problems
Hydrostatics

Directions: On this worksheet you will practice basic relationships involved in your study of hydrostatics.

Question 1  A 468-gram piece of metal (specific gravity = 7) is suspended from a spring scale and is submerged in water. What force does the spring scale read?
suspended block
Question 2  Two objects labeled K and L have equal mass but densities of 0.95Do and Do, respectively. Each of these objects floats after being thrown into a deep swimming pool. Which is true about the buoyant forces acting on these objects?
Question 3  The experimental diving bell shown below is lowered from rest at the ocean’s surface and reaches a maximum depth of 120 meters. During the descent, the pressure inside the bell remains constant at 1 atmosphere. The top of the bell has a cross-sectional area A = 7.0 m2. The density of seawater is 1025 kg/m3.



When the bell reaches the ocean bottom what will the minimum force to open the hatch if it has a radius of 0.3 meters?
Question 4  A large rectangular raft is floating on a lake. The surface area of the top of the raft is 7 m2. If the raft has a total volume of 3 m3 and is composed of a material having a density of 677 kg/m3, how much of the raft's height is underwater?

Question 5  How many 90-kg people can safely sit on the raft in Question #4 without the top of the raft sinking below the surface of the water?
Question 6  Three objects of identical mass attached to strings are suspended in a large tank of liquid, as shown below. Rank the densities of the masses from greatest to smallest.

Question 7  A gas is confined in an enclosed cylinder has a density of 3 g/cm3. The radius of the cylinder is adjusted until it is 3 times as large while its length is 1/4 as great, how will the density of the confined gas change?


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