Work and Energy

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Work and Energy
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Work
?Work A Force acting through a distance
? Work Force x DistanceWFxd
? Units Newton x meter or, Nm
(English lbft)
? Units 1 Nm 1 Joule (J)
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Fig 6.2a, p.173
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d
d
? Work Force x DistanceWFxd 600 N x 1.00
m 600 Nm
Fig 6.2b, p.173
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Fig 6.3b, p.174
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? Work Force x DistanceWFxd (1kg x 9.81
m/s2) x 2 m 9.81 N x 2 m
19.62 Nm
Fig 6.6, p.176
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? Force must be in same direction as the motion?
So, in this case the man does no work on the
barbell
Fig 6.4a, p.175
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Fig 6.4b, p.175
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Fig 6.11, p.182
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?Energy The ability to do work
?Units Joule (J) (Unit for work also)
?Forms of Energy - Mechanical - Heat -
Chemical - Electromagnetic - Nuclear
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?Mechanical Energy - Energy associated with
motion - Includes - Moving water - Wind -
Motors - Sound
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(No Transcript)
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?Heat Energy - Energy of vibrating molecules -
Faster movement more heat - Friction causes
heat - Adding or removing heat
causes temperature changes
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?Chemical Energy - Energy needed to bond atoms
together - When bonds broken energy is
needed - When bonds form energy is
released - Fuels and food contain chemical
energy
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?Electromagnetic Energy - Electricity -
Light - Radio Waves - X-rays - Microwaves
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?Nuclear Energy - Nuclear Fission - Nuclear
Fusion on sun - involves joining nuclei of two
hydrogen atoms to produce helium
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Fig 6.p184, p.184
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Fig 6.12, p.185
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Fig 6.13, p.185
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Fig 6.p186, p.186
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Fig 6.15, p.189
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Fig 6.16 , p.189
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Fig 6.p191, p.191
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Fig 6.17, p.192
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Fig. 6.P17, p.203
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Fig. 6.P44, p.205
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Fig. 6.P55, p.205
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