foundations for physics dr. gluck unit 1.1
DESCRIPTION
Foundations for Physics Dr. Gluck Unit 1.1 Laws of Motion, Velocity, Displacement, and Acceleration PS 3-(9-11)-8a Text Chapter 1: Describing the Physical Universe. Guiding Questions. How is adding displacement different from adding distance? - PowerPoint PPT PresentationTRANSCRIPT
Foundations for PhysicsDr. Gluck
Unit 1.1Laws of Motion, Velocity, Displacement, and
AccelerationPS 3-(9-11)-8a
Text Chapter 1: Describing the Physical Universe
Guiding Questions• How is adding displacement
different from adding distance?
• How is calculating speed different from calculating velocity?
• How is determining velocity different than determining speed or acceleration?
• How can we determine position, speed, or velocity from a graph?
Forces and MotionDescribing the Physical Universe
1.1 What is Physics?
1.2 Distance and Time
1.3 Speed
Chapter 1.1 Objectives and Vocabulary
natural lawexperimentanalysismasssystemvariablemacroscopicscientific methodindependent variabledependent variablehypothesiscontrolled variable experimental variablemodel
Explain what makes up the universe.
Describe how the scientific method is used.
Explain the effects of energy on a system.
What is Physics?
•Finding the simplest and least complicated explanation.
•Observe HOW things work.
•Form connections between cause and effect.
Universe
Everything around us
Matter Energy
Has mass and
volume
Has the ability
to cause
change
Frame of Reference
• System to determine or measure position based on the motion/position of the observer.
Natural Laws
•All events in nature obey natural laws.
•Natural laws do not change.
•Consistency - reliability of successive results or events
•Accuracy - how close is the result to the true value?
•Natural laws are based on human experiences.
Experimentation - carefully designed simulations that are used to analyze (interpret and understand) natural laws.
Experiments have variables - factors that effect the behavior of the experimental system.
2 types of variables:
Experimental - looked at in the experiment
Independent Variable – controlled by YOU
Dependent Variable – changes based on IV
Control - something to compare the experimental variable to..
•What are the variables?
•Independent variable
•Dependent variable
System- collection of matter and processes that occur in a certain
space and can be studied.
Energy of a SystemEnergy is the ability to cause
change.
Energy can take on many forms.
The forms of energy can change from one to another but the TOTAL amount of energy in a system is CONSTANT.
Systems in nature want to be stable. Stability is important.
In nature, stability means LOW ENERGY.
Therefore, in nature, systems tend to go from higher energy levels toward lower energy levels in order to reach stability. This is true in all aspects of science.. HIGH E = UNSTABLE
LOW E = STABLE
Car is unstable due to its height.
HIGH POTENTIAL ENERGY
Car is more stable at a
lower heightLOW POTENTIAL
ENERGY
1A Investigation: Time, Distance, and Speed
Key Question:
How is motion described and measured in Physics?
*Students read text section 1.2AFTER Investigation 1A
1A Investigation Topics
Learn uses and functions of CPO Timer and photogates.
Set car to travel at constant speed.
Measure time intervals.
Calculate speed from time interval measurements.
Graph position vs. timer for car traveling down track.
Chapter 1.2 Objectives and Vocabulary
distancelengthEnglish systemmetric systemtime intervalsecond
Express distance measurements in both English and metric units.
Measure time intervals in mixed units.
Distinguish between independent and dependent variables.
Construct graphs. Convert between different
units of time.
Three Three targets with targets with three arrows three arrows each to each to shoot.shoot.
Can you hit the bull's-eye?Can you hit the bull's-eye?
Both accurate and precise
Precise but not accurate
Neither accurate nor precise
How do they How do they compare?compare?
Can you define accuracy vs. precision?Can you define accuracy vs. precision?
AccuracyCloseness to the true value
PrecisionReproducibility of results
Our measurements:
1.must be precise (reproducible)2.Should be accurate (as close to the true value as possible)3. must have units to communicate value
In physics, we use two common measurements:
DISTANCE
Amount of space between two points
Measured in units of length
TIME
1.A particular moment (12:00 pm)
2.A quantity of time (3 hours)
3. Time Interval – “how much time did it take…?”
Convert 3:45:10 into seconds.
3 hrs x 3600 sec = 10,800 sec hr
45 min x 60 sec = 2,700 sec min
= 10 sec
ANSWER:13,510 seconds
Independent variable
Dep
en
den
t vari
ab
le
1B Investigation: Systems, Energy and Change
Key Questions:
Why do things change?
Why do things change by only a certain amount?
*Students read text section 1.3 AFTER Investigation 1B
1B Investigation TopicsMeasure time intervals.
Calculate speed from time interval measurements.
Identify variables in an experiment.
Identify dependent and independent variables.
Control variables in an experiment.
Compare speeds and energy of car.
Chapter 1.3 Objectives and Vocabulary
speed
constant speed
Define speed.
Express an object's speed using various units.
Calculate speed, distance or time given two of the three quantities.
List the steps for solving physics problems.
What does this sign tell you??
25 miles per hour
25 miles hour
“per” means “divide”
Speed (v=d/t)Distance divided by time.
•If you follow the speed limit, you will travel 25 miles in 1 hour.
Is a ratio: a relationship between distance and time
d
tv