CH 13 Liquids Flashcards
Pressure
The force per unit area that one object exerts on another
Pressure equation
Pressure = Force / area
Pressure depends on the area
The area over which force is distributed
When you stand on one foot instead of two, the force you exert on the floor is ?
The same.
The between force and pressure! The weight is the same, it is the force
When you stand on one foot instead of two, the pressure you exert on the floor is
More.Twice as much, in fact! Pressure is no the same as force.
The deeper you swim
The greater the pressure.
Pressure is ________ dependent not _________ dependent
Depth dependent and not volume dependent.
Pressures act _______ in all directions
Equally
Whatever the shape of a container pressure is
At any particular depth is the same.
Liquid pressure =
weight density ´ depth
Water pressure provided by a water tower is greater if the tower
Water pressure provided by a water tower is greater if the tower is TALLER.
Water pressure acts ________ to surfaces of a container and on objects inside the liquid.
Acts perpendicular to surfaces
Buoyancy in a Liquid =
= support force
Buoyancy
The apparent loss of weight of a submerged object.
Lifting a heavy object under water is easier than lifting it on the surface because
Because the water exerts an additional SUPPORT force. This extra UPWARD, support force is called the BUOYANT force.
With buoyancy the ________ _________ on the side cancel each other out.
Force vectors
How many forces actually form the net force on a submerged body in a fluid?
B.Two—buoyancy and the force due to gravity
The volume of the water displaced is _______ to the ________ of the stone [object in the water].
EQUAL to the volume
Displacement rule
A completely submerged object always displaces a volume of liquid equal to its own volume.
Archimedes’ Principle
An immersed object is buoyed up by a force equal to the weight of the fluid it displaces.
The reason a person finds it easier to float in saltwater compared with freshwater is that in saltwater
Neither. A floating person has the same buoyant force whatever the density of water. A person floats higher because a smaller volume of the denser saltwater is displaced.
Whether an object floats or sinks depends upon the
- volume of the object.
- volume of the fluid displaced.
For an object to float:
The buoyant force (weight of the liquid it displaces) must be equal or more than weight of the object itself.
Principle of flotation
A floating object displaces a weight of fluid equal to its own weight.
Float or sink rule #1
- An object more dense than the fluid in which it is immersed will sink.
Float or sink rule #2
- An object less dense than the fluid in which it is immersed will float.
Float or sink rule #3
- An object having a density equal to the density of the fluid in which it is immersed will neither sink nor float. = for all fluids
A crocodile increases its ________ in order to sink as it approaches prey.
Density
Test ?’s
Water pressure at the bottom of a lake depends on the
C. depth of the lake.
Test ?’s
When a submarine takes water into its ballast tanks, its density _______.
increases
Test ?’s
**The buoyant force that acts on a 20,000-N ship is **
a.20,000 N.
Two solid blocks of identical size are submerged in water. One block is lead and the other is aluminum. Upon which is the buoyant force greater?
B.Same on both blocks
When you float in saltwater and not in freshwater, the volume of water displaced is
a.less and the buoyant force is unchanged.
The volume of water displaced is less, its weight equals your weight. Ma
The buoyant force that normally acts on a fish under water is
C.equal to its weight.
however deep a fish swims, it displaces a weight of water is the same as
Pascal’s Principle - 17th century
A change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid.
T/F Pascal’s Principle applies to all fluids, which include gases and liquids.
True.
a balloon squeezes one end it gets tighter as the air is moved to the ot
The contractive tendency of the surface of liquids is due to ______ ________
surface tension
Drops of any kind are spherical because
their surfaces tend to contract and force each drop into the shape having the least surface area for a given volume – a sphere.
1
Factors affecting surface tension:
#1
- The type of liquid
– Water has greater surface tension than oil.
Factors affecting surface tension:
#2
- What is mixed with the liquid
– Soapy water has lower surface tension than water without soap.
Factors affecting surface tension:
#3
- Temperature of the liquid
– The molecules in a hot liquid have higher energy and are not bou
Factors affecting surface tension:
#3
- Temperature of the liquid
– The molecules in a hot liquid have higher energy and are not bou
