Zusammenfassung der Ressource
Physics Exam 1
- Chapter 1. Introduction
- 1.What is Physics?
- Physics is the science of matter and energy, and
the interactions between them. The laws of
Physics enables us to predict and understand the
way the universe works.
- 2.Problem Solving
- Problem solving is an essential part of
physics, problems may be quantitative with
a precise answer, or they may be
conceptual. For some problems, you may
need to use common sense reasoning to
estimate the values of important quantities.
- 3.Scientific Notation and Significant Figures
- Scientific Notation is used to express very large and very
small numbers. We can also use prefixes to write very large
or very small numbers. The accuracy of a quantity is
reflected in the number of significant figures used to express
its value.
- 4.Units of Measure
- The Primary units of mechanics involve length, time,
and mass. Most scientific work employs the SI system
of units, in which length is measured in meters, time in
seconds, and mass in kilograms.
- 5.Physical Quantities and Dimensions
- We cannot give a definition of the concepts of length,
time, and mass, but treat them as "givens." Dimensions
of all quantities in mechanics can be expressed in terms
of length I, mass M, and time T.
- 6.The Mathematics of Physics
- Algebra, trigonometry, and vectors are used in Physics. Algebra is essential for solving
systems of equations while coordinate systems require trigonometry and vectors to be
solved. A vector quantity has both magnitude and a direction which can be added
graphically or in terms of their components.
- Chapter 3: Forces and Motion in One Dimension
- Motion Along a Line
- Kinematic equations
- Normal Force
- Acts perpendicularly to plane of contact
- Occur whenever two surfaces of two objects contact each other
- Free Body Diagrams
- Used for analysis using Newton's Second Law
- Simplified diagram showing all the forces acting on each
object involved in the problem
- Friction
- Force of friction
opposes the
motion
- Kinetic Friction
- When object is moving
- Static Friction
- When object is stationary
- Free Fall Motion
- When an object is falling under the sole
influence of gravity
- A free-falling object has an acceleration of
9.8m/s^2 downwards
- Tension
- Force transmitted through a rope
from one end to another
- An "ideal" cord has zero mass, does
not stretch and has equal tension
throughout the cord
- Chapter 2
- Motion
- Position
- The position of an object describes it's location relative to some origin or other reference point
- Displacement is the change in an object's position. It depends only on the beginning and ending positions
- Δr=rf −ri
- Velocity
- Velocity is a vector that measures how fast and in what direction something moves
- Average Velocity
- Vav =Δr/Δt
- vav,x = (x2 −x1) /(t2 −t1)
- Instantaneous Velocity
- v = lim Δt→0 (Δr / Δt)
- Acceleration
- Average Acceleration
- aav =Δv /Δt
- Finding Acceleration From A Graph
- The acceleration is the slope of a velocity-time graph
- Instantaneous Acceleratoin
- a = lim Δt→0 (Δv / Δt)
- Forces
- SI Unit
- Newtons (N)
- Newtons= kg x (m/s^2)
- Force= Mass x Acceleration
- F=ma
- Newton's Laws
- Newton's First Law
- Every object in a state of uniform motion tends to remain in that state of motion unless an external force is
applied to it.
- Newton's Second Law
- The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Acceleration
and force are vectors (as indicated by their symbols being displayed in slant bold font); in this law the direction of
the force vector is the same as the direction of the acceleration vector.
- The total force on an object is the sum of these individual forces
- Newton's Third Law
- For every action there is an equal and opposite reaction.
- Chapter 4
- Statics
- Deals with objects at rest
- Statics and Equilibrium
- Statics is an area of mechanics dealing with problems in which the velocity and acceleration are both zero
- if the acceleration is zero then...
- EF=F1+F2+K=0
- Newton's 2nd Law Applications
- Inclines
- Normal force is perpendicular to the incline
- To not slip...
- Friction must be greater than the static friction times N
- Projectile Motion
- ax=0
- ay=-g
- Relationships among displacement, velocity, acceleration, and time for constant acceleration apply directly