Presentation on theme: "COMT 3911 Some Fundamentals. COMT 3912 Fundamentals The Metric System What is a “Wave” Calculations in “Decibels”"— Presentation transcript:
COMT 3911 Some Fundamentals
COMT 3912 Fundamentals The Metric System What is a “Wave” Calculations in “Decibels”
COMT 3913 The Metric System Based on MKS - Meters, Kilograms, Seconds 1 m is about 3 feet 1 kg is about 2.2 pounds
COMT 3914 “Scientific” Notation Large and small numbers are written as a number “around” 1, multiplied by ten raised to the proper power –41,400 = 4.14x10 4 –1,000,000,000,000 = 1x10 12 – = 5.43x10 -5
COMT 3915 Try It
COMT 3916 And the answers are = 9.845x = 7.68x = 1.2x = 3x = 4x10 -10
COMT 3917 Number Prefixes Prefix designates powers of 10 m c k M G
COMT 3918 Try it Convert 10000m to km Convert 1mm to m Convert 3mm to km Convert 13km to m
COMT 3919 The Result 10000m = 10km 1mm = 0.001m = m 3mm = 3x10 -6 km 13km = 1.3x m
COMT Some Numbers Speed of light: 3x10 8 m/s or 300,000,000 m/s or 300,000 km/s Mass of the earth: 5.98x10 24 kg Radius of the earth: 6.38x10 6 m Speed of sound in air: 343 m/s
COMT Waves A wave can be roughly defined as an organized series of disturbances traveling through space or through a medium.
COMT “Ripples” - Surface Waves
COMT At a fixed time...
COMT At one point along the surface
COMT Measurements Amplitude (A) Wavelength ( ) in meters (with prefix) Number of cycles per second is frequency (f) In 1/sec = Hz
COMT Types of Waves Sound - pressure disturbance in a medium (air, water, etc.) Surface - disturbance in the “normal” position of the surface Electromagnetic - alternating electric and magnetic disturbances in a medium or in a vacuum.
COMT For all waves: The speed of the wave is equal to the product of the wavelength and the frequency.
COMT Some Examples Speed of light: 3x10 8 m/s Find the wavelength for each case –AC Current: 60Hz –FM Radio: 90MHz –Ka Band Satellite: 20GHz –Ultraviolet Light: Hz The speed of the wave is equal to the product of the wavelength and the frequency.
COMT Some Examples Speed of light: 3x10 8 m/s Find the wavelength for each case –AC Current: 60Hz = 5000km –FM Radio: 90MHz = 3.33m –Ka Band Satellite: 20GHz = 15mm –Ultraviolet Light: Hz = 3x10 -7 m The speed of the wave is equal to the product of the wavelength and the frequency.