Chapter 9 Forces and Fluids Pressure, Hydraulics,...
6
Chapter 9 Pressure, Hydraulics and Pneumatics.notebook 1 February 18, 2017 Jan 1311:07 AM Chapter 9 Forces and Fluids Jan 1510:44 AM Pressure, Hydraulics, and Pneumatics Jan 1510:49 AM Jan 1510:49 AM The force acting on a certain area of a surface. The larger the force, the greater the pressure. The smaller the area, the greater the pressure. Unit = Pascal (Pa) Pressure Jan 1510:52 AM Jan 1510:53 AM
Transcript of Chapter 9 Forces and Fluids Pressure, Hydraulics,...
Chapter 9 Pressure, Hydraulics and Pneumatics.notebook
1
February 18, 2017
Jan 1311:07 AM
Chapter 9 Forces and Fluids
Jan 1510:44 AM
Pressure, Hydraulics, and Pneumatics
Jan 1510:49 AM Jan 1510:49 AM
The force acting on a certain area of a surface.
The larger the force, the greater the pressure.
The smaller the area, the greater the pressure.
Unit = Pascal (Pa)
Pressure
Jan 1510:52 AM Jan 1510:53 AM
Chapter 9 Pressure, Hydraulics and Pneumatics.notebook
2
February 18, 2017
Jan 1510:54 AM
The amount of force that is exerted by the weight of the atmosphere.
Atmospheric Pressure
Jan 1511:06 AM
The unit for pressure is the ____________
where,1 Pa = 1 N/m2
Force = N
Area = m2
Calculating Pressure
Pascal
Feb 88:31 AM
Therefore,
F = P A P = F A = F P A
x
Jan 213:18 PM
Examples.1. An aquarium is filled with water that weighs 10 000N. If the base of the aquarium has an area of 1.6 m², what pressure does the water exert on its base?
F = 10 000NA = 1.6 m2
P = ?
P = F A
P= 10 000N
1.6m²
P = 6250 Pa
Jan 213:28 PM
2. If the atmospheric pressure is 101 200 Pa and you are holding your hand, the atmosphere is exerting a force on your hand. If the area of your palm is 0.006m², calculate the force on your hand.
P = 101 200 Pa F = P x AA = 0.006m2 F = 101 200 Pa x 0.006m2
F = ? F = 607 N
Jan 213:29 PM
3. The weight of water in a glass is 4.9 N. If the water is exerting a pressure of 1700 Pa on the bottom of the glass, what is the area of the bottom of the glass?
F = 4.9 NP = 1700 Pa
A = F P
A = 4.9 N 1700 Pa
A = 0.0029 m²
Chapter 9 Pressure, Hydraulics and Pneumatics.notebook
3
February 18, 2017
Jan 213:30 PM
Worksheet
BLM 335
Feb 136:02 PM
Why can a person wearing snowshoes walk across a section of deep, soft snow without sinking?
Snowshoes provide a greater area, so there is less pressure concentrated into a smaller area.
Jan 229:19 AM
How can the nozzle on a garden hose be used to create a faster flow of water?
By decreasing the surface that the water can come out of, you increase the pressure. This makes the water appear to be faster.
Feb 1210:28 AM
Pascal's LawPressure applied to an enclosed fluid is transmitted with equal force throughout the entire container.
This is the principle behind hydraulic and pneumatic systems.
Feb 113:42 PM
Hydraulics is the study of pressure in liquids.
Devices that transmit applied force through a liquid to move something else are called hydraulic systems.
Hydraulics
Jan 229:27 AM
In most hydraulic systems, a force is exerted on a continuous, enclosed liquid.
This applied force creates pressure that moves the liquid through a series of tubes, pipes, or hoses, which causes a motion at the other end of a hydraulic system.
Chapter 9 Pressure, Hydraulics and Pneumatics.notebook
4
February 18, 2017
Feb 1210:48 AM
Liquids are an incompressible fluid (cannot be squeezed into a smaller volume)
The liquid must be enclosed in a tube or pipe.
The pressure produced will exert in all directions equally.
This pressure will cause motion at the other end of the hydraulic system.
Feb 1210:56 AM
Examples of hydraulic systems:
1. A dentist's or hairdresser's chair
2. Jaws of Life
3. Dump trucks
Feb 1211:02 AM
Pneumatic Systems Just like other fluids, air exerts pressure on everything that surrounds it. The study of pressure in gases is called pneumatics.
In pneumatic systems, a gas transmits a force exerted on the gas in an enclosed space.
Pneumatic systems are similar to hydraulic systems, except that gases are used instead of liquids.
Compressors are necessary as gases can be compressed. They build up the air pressure, and then when the pressure is released, a strong, steady force is created.
Jan 229:44 AM
Examples of pneumatic systems:
1. Jackhammers
2. Shock absorbers on a bicycle
Feb 117:02 PM
Property Hydraulic System
Pneumatic System
State Liquid Gas
Volume Definite Indefinite
Pressure Not compressible Compressible
Pascals's Law: Hydraulics and PneumaticsPascal's Law applies to both hydraulics and pneumatics:
Feb 1211:26 AM
Examples of Pascal's Law:
car lift or hoist hydraulic jack automobile braking system air compressors automobile/bicycle tires
Chapter 9 Pressure, Hydraulics and Pneumatics.notebook
5
February 18, 2017
Jan 229:45 AM
Video Clips
Jan 2310:25 AM
Increasing the pressure on a gas results in a decrease in volume when temperature is held constant.
Pressure and Volume
Feb 136:17 PM
Increasing the temperature of a gas results in an increase in volume when pressure is held constant.
Jan 2310:53 AM
Increasing the temperature of a gas results in an increase in pressure when volume is held constant.
Jan 231:51 PM
Examples that illustrate the relationship among pressure, volume and temperature when gaseous fluids are compressed or heated:
1. Propane Cylinders
(increase in pressurewith a decrease involume at constanttemperature)(ii) heating an aerosolpressure volume
Jan 232:02 PM
When the propane is inside the tank it is under pressure, which causes it to be a liquid. When you release the pressure (open the valve), the liquid evaporates and comes out as a gas.
Chapter 9 Pressure, Hydraulics and Pneumatics.notebook
6
February 18, 2017
Jan 232:04 PM
2. Aerosol can
temperature pressure
Feb 53:26 PM
Why does this symbol appear on aerosol cans?
If the aerosol can cannot spray anymore then the pressure inside and outside the can are the same. However if you heat the can, the pressure builds up inside and because the can is sealed it has no where to go and it explodes.
