WORK
Work is the energy transferred into or
out of a system through the action of a force. Work done against
gravity can be found using the equation Work equals Force times height
or W = Fh. Since F = mg we can use the equation W = mgh. (m =
mass, g = gravity, or 9.81
m/s² and h = height). Lets try an example.
<http://alaskadogsled.com/photos.htm>
The Yukon Quest is known as "The
toughest sled dog race in the world!" There are many challenges that
mushers face which include great elevation changes and harsh weather
conditions. Between the checkpoints of Dawson City and Pelly Crossing
lies King Solomon's Dome. The elevation at Dawson City is 370 meters
and the summit of King Solomon's Dome is 1,158 meters. Find the amount
of
work (in Joules) it takes to mush a dog team of ten
dogs from Dawson City to the top of King Solomon's
Dome. Given that the mass of the sled is 20 kg , the driver is 80 kg,
mandatory equipment is 45 kg, and the dogs each weigh approximately 20
kg.
From the above equation W = mgh.
m = 20 (sled) + 80 (driver) + 45 (equipment) + 20*10 (dogs)
m = 345 kg
g = 9.81 m/s² (gravity constant)
h = 1158 m - 370 m = 788 m
W = (345 kg) * (9.81 m/s²) * (788 m)
W = 2666946 Joules That's a lot of
Work!!!
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