unit 1 Flashcards
what is a field
your academic training. what you studied in school
what is a focus
how you work in your job
examples of a focus
design, process, production
what does ASME international stand for
American society of mechanical engineers
why was ASME international created
boilers used to run power plants were exploding
what was the first code written by ASME international
rules for conducting boiler tests
what is a code
a standard that is being passed as law
what is a standard
a recommended way of doing something
what else is ASME international involved in other than creating codes and standards
- professional development
- scientific journals
what should every calculation have
a numerical value and dimensions with units (unless dimensionless)
what is a dimension
a generic description of a physical quantity without units (length, mass, time)
what is a unit
measure of a dimension in a specific system (us customary, international)
what are base units
fundamental units
what are examples of base units in SI
second, kelvin, mole, meter, kg
what are derived units
a combination of base units
what are examples of derived units in SI
micron, liter, pascal, jule, watt, cm, newton
what are order of magnitude prefixes
the describe very large or very small numbers
examples of order of magnitude prefixes
terawatt: 10^12 W
nanosecond: 10^-9 sec
mega: 10^6
milli: 10^-3
viscosity unit
kg/ (m x s)
what are the 3 problem solving steps
- approach
- solution
- discussion
what do you do during the approach step of problem solving
write down your given info and summary
what do you do during the solution step of problem solving
sketch, substitute numbers an units into the equation, show work, simplify, solve, round
what do you do during the discussion step of problem solving
major calculations and check your work
what does dimensional consistency (homogeneity) say
dimensions (units) must cancel out on each side of the equation
what does newton’s 1st law say
every object remains at rest or uniform motion of a constant velocity unless acted upon by an external, unbalanced force
what do we know newtons 1st law as
inertia/ momentum
what does newtons 2nd law say
an object with mass, m, subject to force, f, experiences acceleration in the same direction as the force
what equation do we associate with newtons 2nd law
F=ma
when there is a static equilibrium what does the f=ma equation equal
f=ma=0
what does newtons 3rd law say
the force of an action exerted by body 1 onto body 2 is equal, opposite, and collinear
summary of newton’s 3rd law
every action has an equal and opposite reaction
what are scalers
quantities described by magnitude and units
why are 4 examples of scalers
speed, mass, pressure, distance (magnitude)
what are vectors
quantities described by magnitude and direction
what does the law of sines say
a/sinA= b/sinB= c/sinC
what does the law of cos say
c^2= a^2 + b^2 -2ab cos(c)
what are the 3 steps of the vector polygon method
- draw 1 vector in appropriate length and direction
- draw 2nd vector beginning at the tip of the 1st
- the resultant should connect the vectors
what are the 3 steps of the vector algebra method
- break each vector into rectangular form
- add the x components for Rx
- repeat in the y direction
what is a moment
the tendency of a force to cause a rotation. the rotation does not have to actually occur.
is counterclockwise positive or negative
positive
what do engineers do
- structures
- materials
- system integrations
- services
what is structures
large buildings used in everyday life
what is materials
mining, processing, developing
what is system integrations
making different systems work together
what is services
supply chains- Fedex, amazon, etc
what do mechanical engineers do
- research
-design
-develop
-test
-manufacture
tools, technology, machinery…
what is the weight equation
weight= mass x gravity
slug unit
(lbs x s^2)/ ft
what is a newton
(kg x m)/ s^2
units of Mo in SI
N x m
units of Mo in USCS
theta x distance
what are the 3 static equilibrium equations
- ΣFx, i = 0
- ΣFy, i = 0
- ΣMo, i = 0
particle
a point in space so small it doesn’t have any dimensions (no moments)
rigid body
forces distributed over dimension in x,y directions
free body diagrams
sketch of the system you are analyzing
what are the 3 steps to drawing a free body diagram
- draw component under analysis and isolate from it’s surroundings
- draw coordinate system
- dimensions, angles, direction of gravity, etc.
what is included when you isolate the component
only applied forces and reaction forces
what do you do if a reaction force direction is unknown
you assume (guess)
if you assume the directions, how do you know if you assumed correctly?
if the reaction force is >0, the direction is correct. if the reaction force is <0, the direction is incorrect
