PHYS 1401 WTC FINAL EXAM
QUESTIONS WITH CORRECT ANSWERS
To |triple |both |the |pressure |and |the |volume |of |a |fixed |amount |of |an |ideal |gas, |you |would |multiply |its |
absolute |temperature |by |- |VERIFIED |ANSWER✔✔-9
Two |unequal |masses |m |and |2m |are |attached |to |a |thin |bar |of |negligible |mass |that |rotates |about |an |
axis |perpendicular |to |the |bar. |When |m |is |a |distance |2d |from |the |axis |and |2m |is |a |distance |d |from |the
|axis, |the |moment |of |inertia |of |this |combination |is |I. |- |VERIFIED |ANSWER✔✔-3/2 |I
A |string |of |length |0.780 |m |is |vibrating |at |150 |Hz |in |its |second |harmonic |and |producing |sound |that |
moves |at |340 |m/s. |- |VERIFIED |ANSWER✔✔-- |The |wavelength |of |the |sound |is |2.27 |m. |
- |The |frequency |of |the |sound |is |150 |Hz.
A |cylindrical |metal |bar |conducts |heat |at |a |rate |R |from |a |hot |object |to |a |cold |object.
If |both |its |length |and |diameter |are |doubled, |it |will |conduct |heat |at |a |rate |(a) |R |- |VERIFIED |
ANSWER✔✔-2R
You |decide |to |take |a |nice |hot |bath |but |discover |that |your |thoughtless |roommate |has |used |up |most |
of |the |hot |water. |You |fill |the |tub |with |290 |kg |of |30.0 |∘C |water |and |attempt |to |warm |it |further |by |
pouring |in |5.00 |kg |of |boiling |water |from |the |stove. |- |VERIFIED |ANSWER✔✔-- |irreversible |
- |(290)(Tf |- |30) |- |(5)(100 |- |Tf) |= |0 |
Tf |= |32
An |object |of |mass |M |suspended |by |a |spring |vibrates |with |a |period |T. |If |this |object |is |replaced |by |one |
of |mass |4 |M, |the |new |object |vibrates |with |a |period |- |VERIFIED |ANSWER✔✔-2T
A |ball |of |mass |0.500 |kg |is |whirled |in |a |horizontal |circle |at |the |end |of |a |light |string |50.0 |cm |long |at |a |
speed |of |3.00 |m/s. |If |the |string |is |lengthened |to |1.50 |m |while |the |ball |is |being |twirled, |then |the |
speed |of |the |ball |will |now |be |- |VERIFIED |ANSWER✔✔-(.5 |m)(3 |m/s) |= |(1.5 |m)(?)
1 |m/s
, The |thermal |conductivity |of |concrete |is |0.80 |W/(m⋅K), |and |the |thermal |conductivity |of |a |certain |wood
|is |0.10 |W/(m⋅K). |How |thick |would |a |solid |concrete |wall |have |to |be |to |have |the |same |rate |of |heat |
flow |as |an |7.2-cm-thick |solid |wall |of |this |wood? |Both |walls |have |the |same |surface |area |and |the |same
|interior |and |exterior |temperatures. |- |VERIFIED |ANSWER✔✔-(0.80)(.0072 |m) |/ |(0.10) |= |0.0576
If |the |gauge |pressure |at |a |depth |d |in |a |lake |is |P, |the |gauge |pressure |at |a |depth |9d |will |be |- |VERIFIED |
ANSWER✔✔-9P
You |are |standing |between |two |stereo |speakers |that |are |emitting |sound |of |wavelength |9.80 |cm |in |
step |with |each |other. |They |are |very |far |apart |compared |with |that |wavelength. |
If |you |start |in |the |middle |and |walk |a |distance |x |directly |toward |one |speaker, |you |observe |that |the |
sound |from |these |speakers |first |cancels |when |x |is |equal |to |- |VERIFIED |ANSWER✔✔-9.8 |/ |4 |= |2.45
Oxygen |molecules |are |16 |times |more |massive |than |hydrogen |molecules. |If |samples |of |these |two |
gases |are |at |the |same |temperature, |what |must |be |true |about |the |motion |of |the |molecules? |(There |
may |be |more |than |one |correct |choice.) |- |VERIFIED |ANSWER✔✔-- |The |average |kinetic |energy |is |the |
same |for |both |gases.
- |The |rms |speed |of |the |hydrogen |molecules |is |4 |times |greater |than |that |of |the |oxygen |molecules.
A |disk |starts |from |rest |and |rotates |with |constant |angular |acceleration, |If |the |angular |velocity |is |ω |at |
the |end |of |the |first |two |revolutions, |then |at |the |end |of |the |first |6vrevolutions |it |will |be |- |VERIFIED |
ANSWER✔✔-sqrt |of |3
A |horizontal |pipe |with |water |flowing |through |it |has |a |circular |cross |section |that |varies |in |diameter. |
The |diameter |at |the |wide |section |is |5 |times |the |diameter |at |the |narrow |section. |If |the |rate |of |flow |of
|the |water |in |the |narrow |section |is |9.0 |L/min, |the |rate |of |flow |of |the |water |in |the |wide |section |is |- |
VERIFIED |ANSWER✔✔-diameter |doesn't |change |rate |of |flow |if |it |gets |bigger |so |9.0 |L/min
A |bicycle |wheel |rotating |at |a |rate |of |18 |rad/s |begins |to |accelerate |at |a |rate |of |6 |rad/s2. |After |3 |
seconds |the |rate |of |rotation |will |be |- |VERIFIED |ANSWER✔✔-18 |+ |(6)(3) |= |36
A |heavy |solid |disk |rotating |freely |and |slowed |only |by |friction |applied |at |its |outer |edge |takes |100 |
seconds |to |come |to |a |stop. |If |the |disk |had |twice |the |radius |and |twice |the |mass, |but |the |frictional |
QUESTIONS WITH CORRECT ANSWERS
To |triple |both |the |pressure |and |the |volume |of |a |fixed |amount |of |an |ideal |gas, |you |would |multiply |its |
absolute |temperature |by |- |VERIFIED |ANSWER✔✔-9
Two |unequal |masses |m |and |2m |are |attached |to |a |thin |bar |of |negligible |mass |that |rotates |about |an |
axis |perpendicular |to |the |bar. |When |m |is |a |distance |2d |from |the |axis |and |2m |is |a |distance |d |from |the
|axis, |the |moment |of |inertia |of |this |combination |is |I. |- |VERIFIED |ANSWER✔✔-3/2 |I
A |string |of |length |0.780 |m |is |vibrating |at |150 |Hz |in |its |second |harmonic |and |producing |sound |that |
moves |at |340 |m/s. |- |VERIFIED |ANSWER✔✔-- |The |wavelength |of |the |sound |is |2.27 |m. |
- |The |frequency |of |the |sound |is |150 |Hz.
A |cylindrical |metal |bar |conducts |heat |at |a |rate |R |from |a |hot |object |to |a |cold |object.
If |both |its |length |and |diameter |are |doubled, |it |will |conduct |heat |at |a |rate |(a) |R |- |VERIFIED |
ANSWER✔✔-2R
You |decide |to |take |a |nice |hot |bath |but |discover |that |your |thoughtless |roommate |has |used |up |most |
of |the |hot |water. |You |fill |the |tub |with |290 |kg |of |30.0 |∘C |water |and |attempt |to |warm |it |further |by |
pouring |in |5.00 |kg |of |boiling |water |from |the |stove. |- |VERIFIED |ANSWER✔✔-- |irreversible |
- |(290)(Tf |- |30) |- |(5)(100 |- |Tf) |= |0 |
Tf |= |32
An |object |of |mass |M |suspended |by |a |spring |vibrates |with |a |period |T. |If |this |object |is |replaced |by |one |
of |mass |4 |M, |the |new |object |vibrates |with |a |period |- |VERIFIED |ANSWER✔✔-2T
A |ball |of |mass |0.500 |kg |is |whirled |in |a |horizontal |circle |at |the |end |of |a |light |string |50.0 |cm |long |at |a |
speed |of |3.00 |m/s. |If |the |string |is |lengthened |to |1.50 |m |while |the |ball |is |being |twirled, |then |the |
speed |of |the |ball |will |now |be |- |VERIFIED |ANSWER✔✔-(.5 |m)(3 |m/s) |= |(1.5 |m)(?)
1 |m/s
, The |thermal |conductivity |of |concrete |is |0.80 |W/(m⋅K), |and |the |thermal |conductivity |of |a |certain |wood
|is |0.10 |W/(m⋅K). |How |thick |would |a |solid |concrete |wall |have |to |be |to |have |the |same |rate |of |heat |
flow |as |an |7.2-cm-thick |solid |wall |of |this |wood? |Both |walls |have |the |same |surface |area |and |the |same
|interior |and |exterior |temperatures. |- |VERIFIED |ANSWER✔✔-(0.80)(.0072 |m) |/ |(0.10) |= |0.0576
If |the |gauge |pressure |at |a |depth |d |in |a |lake |is |P, |the |gauge |pressure |at |a |depth |9d |will |be |- |VERIFIED |
ANSWER✔✔-9P
You |are |standing |between |two |stereo |speakers |that |are |emitting |sound |of |wavelength |9.80 |cm |in |
step |with |each |other. |They |are |very |far |apart |compared |with |that |wavelength. |
If |you |start |in |the |middle |and |walk |a |distance |x |directly |toward |one |speaker, |you |observe |that |the |
sound |from |these |speakers |first |cancels |when |x |is |equal |to |- |VERIFIED |ANSWER✔✔-9.8 |/ |4 |= |2.45
Oxygen |molecules |are |16 |times |more |massive |than |hydrogen |molecules. |If |samples |of |these |two |
gases |are |at |the |same |temperature, |what |must |be |true |about |the |motion |of |the |molecules? |(There |
may |be |more |than |one |correct |choice.) |- |VERIFIED |ANSWER✔✔-- |The |average |kinetic |energy |is |the |
same |for |both |gases.
- |The |rms |speed |of |the |hydrogen |molecules |is |4 |times |greater |than |that |of |the |oxygen |molecules.
A |disk |starts |from |rest |and |rotates |with |constant |angular |acceleration, |If |the |angular |velocity |is |ω |at |
the |end |of |the |first |two |revolutions, |then |at |the |end |of |the |first |6vrevolutions |it |will |be |- |VERIFIED |
ANSWER✔✔-sqrt |of |3
A |horizontal |pipe |with |water |flowing |through |it |has |a |circular |cross |section |that |varies |in |diameter. |
The |diameter |at |the |wide |section |is |5 |times |the |diameter |at |the |narrow |section. |If |the |rate |of |flow |of
|the |water |in |the |narrow |section |is |9.0 |L/min, |the |rate |of |flow |of |the |water |in |the |wide |section |is |- |
VERIFIED |ANSWER✔✔-diameter |doesn't |change |rate |of |flow |if |it |gets |bigger |so |9.0 |L/min
A |bicycle |wheel |rotating |at |a |rate |of |18 |rad/s |begins |to |accelerate |at |a |rate |of |6 |rad/s2. |After |3 |
seconds |the |rate |of |rotation |will |be |- |VERIFIED |ANSWER✔✔-18 |+ |(6)(3) |= |36
A |heavy |solid |disk |rotating |freely |and |slowed |only |by |friction |applied |at |its |outer |edge |takes |100 |
seconds |to |come |to |a |stop. |If |the |disk |had |twice |the |radius |and |twice |the |mass, |but |the |frictional |
