Classical Physics Mechanics Thermodynamics Waves and Vibrations Electromagnetism Fluids/Materials.
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Transcript of Classical Physics Mechanics Thermodynamics Waves and Vibrations Electromagnetism Fluids/Materials.
Modern Physics•Relativity
•Quantum (atomic)•Nuclear•Particle•Astrophysics
MECHANICSThe branch of Physics that studies the motions of objects and how that motion relates to physical concepts (such as mass and force).
All motiondepends onthe viewpoint or the “Frame of Reference”of the observer.
Distance (d): How far something travels in changing position (total)
EX. I live 5 miles from NPHS. Where do I live?
Scalar QuantityA quantity that has magnitude (size) only. No direction.Ex. Mass, time, temperature
DISPLACEMENT (∆ X or Xf-Xi)
•Change in Position Final position related to initial position *REGARDLESS OF PATH
EX. I live 5 miles from NPHS. Where do I live?
EX. I live 5 miles WEST from NPHS. Where do I live?
*∆X has both magnitude AND direction
DIRECTIONS for VECTORS
•Positive or negative•Up or down•North, South, East or West (NE, etc…)•Coordinates (graph points)•Map gridlines (F4)•Degrees (30◦ North or 30◦ North of East)
Distance is always a positive number, but displacement can be positive OR negative.
EX. Dude walks 5 meters west (-5 units).
Dude walks 7 meters east (+7 units).
Dude walks 4 meters east (+4 units).
∆X= ___________ ?
d= __________ ?
6 meters East
16 meters
AVERAGE SPEED (v)
Def: The total distance traveled
Time to travel distance
v = d
t
OR
*SCALAR quantity
s = d
tr = d
t
SI UNITS: meters/second OR m/s
*km/hr more common
British Engineering Standard: feet/second OR ft/s
*miles/hour (mph) more common*quick convert: mph ≈ twice m/s
Conversion1 m/s = 3.6 km/h = 2.24 mi/h
1 mph = 1.609 km/hr = 0.447 m/s
Usain Bolt holds the record for the 100m dash at 9.58 seconds. Find his average speed in : a.) m/s b.) km/hr c.) mph
100 m/9.58 sec = 10.44 m/s
10.44 m/s X (7.2 km/hr) = 37.58 km/hr ( 2 m/s )
10.44 m/s X (4.5 mph) = 23.49 mph (2 m/s)
Average VelocityHow fast AND in what direction (Vector Quantity)
Average Velocity = displacement/time
EX. The Green Racer drives 80 km west in 1 hour .
The Green Racer then drives 70 km east in 2 hours . Find the Green Racers average speed and average velocity.Speed=d/t……150 km / 3 hr ……… 50 km/hr.
Velocity= ∆X /t…..10 km west /3 hr ….3.3 km/hr west…..OR …..-10 km/3hr….-3.3 km/hr