Physics Topics
• I. MECHANICS
• II. WAVES AND OPTICS
• III. ELECTRICITY AND MAGNETISM
• IV. MODERN PHYSICS
• V. ASTRONOMY
Thinking Back…
• What were some of the tools of a Physicist?
Thinking Back…
• What were some of the tools of a Physicist?
Practice safety & ethicsIdentify & describe equipment
Use SI SystemManipulate formulas
The Scientific MethodUse Lab Report Format
What do you know?
• What is a frame of reference?
What do you know?
• What is a frame of reference?
• A system to determine location or motion of an object.
• How can I tell if something is moving and how fast?
What is acceleration?
What is acceleration?
• Rate of change of speed
• Occurs when we fall or go around a corner
What are forces and how do they commonly occur?
What are forces and how do they commonly occur?
• A force is a push or a pull
• They commonly occur in pairs
What are Newton’s Laws of Motion?
What are Newton’s Laws of Motion?
• #1 Inertia
• #2 F = ma
• #3 Action/Reaction
Motion I
Motion in One Dimension - Quantities, Units, Speed, Position, Distance, Displacement, Velocity,
Vector, Scalar, etc.
Assignment
• Read Chapter 2
• After reading the chapter, complete your Reflections on the chapter.
What you need to know
¤ Motion can be described and analyzed in several ways
¤ How coordinate systems can be used in motion studies
¤ Terms such as displacement, magnitude, vectors
¤ More Terms: scalars, resultant vectors
¤ Interpret motion graphs
¤ Attributes of coordinate system - origin & axis
¤ Models of motion diagrams
Also Needed to Know
¤ Speed, distance (d), and time are scalar quantities.
¤ Velocity, displacement (s), force and acceleration are vectors.
¤ The slope of the distance-time graph is velocity.
¤ The slope of the velocity-time graph is acceleration.
possibilities
• Object not moving, v = 0 m/s
• Object moving at constant velocity
• Object accelerating
• Object decelerating (negative acceleration)
• (Last 2 situations have unbalanced forces acting on them - to be discussed later in the book)
Organizing your thoughts (and units)
• Fundamental Quantities– Length– Mass– Time
• Derived Quantities– Velocity– Density– Volume
• Fundamental Units
– Meter– Kg– Sec
• Derived Units– m/s– g/ml or g/cm3
– m3 or cm3
The "Big Five" Kinematics Equations
Constant acceleration is
assumed
Average Speed/Velocity Defined
v = d / t = ½(Vf + Vo)
Average Acceleration Defined a = ∆v / ∆t = (Vf - Vo) / (tf - to)
Final Velocity of an Accelerating Body
Vf = Vo + a(∆t)
Distance Traveled by an Accelerating Body
d = Vo(∆t) + ½ a(∆t)2
What can I do if I don't know the time interval?
Vf2 - Vo
2 = 2 a d
In the above formulas, a can be replaced with g
g = 9.8 m/s (acceleration on Earth due to gravity when an
object is falling)
Equation of motion for average velocity:
d = vt + di
Online Notes
• http://www.physicsclassroom.com/Default2.html
• This site has information which may be helpful to you in your basic study of Physics.
Scalars & Vectors
• Scalars have magnitude only (a number with units) such as a length of 5.0 m or a speed of 29.3 m/s
• Vectors have magnitude and direction– Velocity: 29.3 m/s North– Force: 25 newtons South– Displacement
Vectors
• Are represented by an arrow
• Length drawn to a chosen scale (1cm:50m/s)
• Direction N S E W
• Vector addition:– Same direction: add– Opposite directions: subtract
Adding Vectors
A
B
R
A
B
R
A + (-B) RA + B R
