MECHANICAL ENGINEERING EXAM #1 FULLY SOLVED
Machine - correct answer -A device that uses energy to do work to accomplish some
desired activity
-They do not produce energy, but they do transmit and transform energy
-Machines can transmit a force, control its motion, and change its direction
-A machine is a system of components
Component - correct answer A small piece that makes up a larger whole. Each
component is there for a specific job, but the sum of components
System - correct answer A combination of components
Mechanical Engineering - correct answer -The designing of machines that contribute to
society and our quality of life
-Mechanical engineers apply the principles of mathematics, chemistry, and physics to
solve real-world problems
Dimension - correct answer -Describes a physical property of anything
-What we are measuring
Base Dimensions - correct answer -Are independent of other dimensions
-They are limited in number
-length, mass, time, temperature, force
Derived Dimension - correct answer -Derived from, or composed of, base dimensions
I.e. Area (length x width), Weight (mass x acceleration), velocity (length/time)
System International (SI) - correct answer The standard system of units that uses base
10 and used in the rest of the world.
-US does not use, but Great Britain does
-Base Units: mass-kilograms (kg), length-meters (m), and time-Seconds (S)
-Force is a derived unit measured in newtons (N)
US Customary - correct answer A system adopted from an old British system of units in
the 13th century
-Engineering system
-Units: length-foot (ft), time-second (s), force-(lbs)
-Mass is a derived unit called a slug
-Political/Economic choice
-Awkward
Length - correct answer The magnitude of something in a particular direction
Mass - correct answer -The amount of atoms and molecules in something
-Matter is energy that has become solid
, -An object gains mass when it gains more energy and vice a versa
-Units: SI-kgs and USA: Slugs, lbs
Temperature - correct answer An indication of kinetic energy of mass at the molecular
level
Area - correct answer -A flat, two dimensional property
-Units of length multiplied by length describe area
-A=length x width
Volume - correct answer -Three-dimensional property measured in units of length times
length times length
-V=length x width x height
Units for Pressure - correct answer -psi
-newtons
-pascals
Metrology - correct answer The branch of science and engineering involving
measurement
Engineers and scientists need a common language - correct answer Dimensions and
units
Dimensions are measured by units - correct answer ...
Units - correct answer Used to measure or quantify
-US Common: Absolute and Gravitational
-SI: absolute
Conversions - correct answer -Allows comparison between different measuring systems
and units
-Necessary to market internationally
Effort - correct answer -The force simple machines use to do work on a single load or
against a single force
-When a simple machine increases a force it is at the expense of a decrease in the
distance the load is moved
-When the work done by the effort just equals the work done by the load, no movement
of the machine will occur
-When the work done by the effort exceeds the work done by the load, the load will
move
Mechanical Advantage - correct answer -If the force needed to operate the machine
(input force) is less than the force being opposed or the load being moved (output force)
-The ratio of the output force divided by the input force
Machine - correct answer -A device that uses energy to do work to accomplish some
desired activity
-They do not produce energy, but they do transmit and transform energy
-Machines can transmit a force, control its motion, and change its direction
-A machine is a system of components
Component - correct answer A small piece that makes up a larger whole. Each
component is there for a specific job, but the sum of components
System - correct answer A combination of components
Mechanical Engineering - correct answer -The designing of machines that contribute to
society and our quality of life
-Mechanical engineers apply the principles of mathematics, chemistry, and physics to
solve real-world problems
Dimension - correct answer -Describes a physical property of anything
-What we are measuring
Base Dimensions - correct answer -Are independent of other dimensions
-They are limited in number
-length, mass, time, temperature, force
Derived Dimension - correct answer -Derived from, or composed of, base dimensions
I.e. Area (length x width), Weight (mass x acceleration), velocity (length/time)
System International (SI) - correct answer The standard system of units that uses base
10 and used in the rest of the world.
-US does not use, but Great Britain does
-Base Units: mass-kilograms (kg), length-meters (m), and time-Seconds (S)
-Force is a derived unit measured in newtons (N)
US Customary - correct answer A system adopted from an old British system of units in
the 13th century
-Engineering system
-Units: length-foot (ft), time-second (s), force-(lbs)
-Mass is a derived unit called a slug
-Political/Economic choice
-Awkward
Length - correct answer The magnitude of something in a particular direction
Mass - correct answer -The amount of atoms and molecules in something
-Matter is energy that has become solid
, -An object gains mass when it gains more energy and vice a versa
-Units: SI-kgs and USA: Slugs, lbs
Temperature - correct answer An indication of kinetic energy of mass at the molecular
level
Area - correct answer -A flat, two dimensional property
-Units of length multiplied by length describe area
-A=length x width
Volume - correct answer -Three-dimensional property measured in units of length times
length times length
-V=length x width x height
Units for Pressure - correct answer -psi
-newtons
-pascals
Metrology - correct answer The branch of science and engineering involving
measurement
Engineers and scientists need a common language - correct answer Dimensions and
units
Dimensions are measured by units - correct answer ...
Units - correct answer Used to measure or quantify
-US Common: Absolute and Gravitational
-SI: absolute
Conversions - correct answer -Allows comparison between different measuring systems
and units
-Necessary to market internationally
Effort - correct answer -The force simple machines use to do work on a single load or
against a single force
-When a simple machine increases a force it is at the expense of a decrease in the
distance the load is moved
-When the work done by the effort just equals the work done by the load, no movement
of the machine will occur
-When the work done by the effort exceeds the work done by the load, the load will
move
Mechanical Advantage - correct answer -If the force needed to operate the machine
(input force) is less than the force being opposed or the load being moved (output force)
-The ratio of the output force divided by the input force
