- #1
JamesL
- 33
- 0
Problem concerning energy...
Heres the problem:
A train with total mass of 2.16 x 10^6 kg rises 750 m while traveling a distance of 51.4 km at an average speed of 9.12 m/s. The frictional force is .8 percent of the weight.
Given: acceleration of gravity is 9.8 m/s.
*Find the kinetic energy of the train in MJ.
*Find the total change in its potential energy in J.
*Find the energy dissipated by friction in J.
*Find the power output of the trains engines in MW.
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On the first part i tried using K = .5mv^2, but that is apparently not the way to do it. I am assuming i have to factor in the work done by friction as well?
That brings me to another question. In trying to find the energy dissipated by friction i did the following:
(mass)(.8 percent)(distance) = Work done by friction
(2.16 x 10^6)(.8/100)(51400) = 8.8819 x 10^8
this is not correct either... so I am puzzled as to what I am doing wrong?
Can anyone point me in the right direction for this problem? Thanks!
Heres the problem:
A train with total mass of 2.16 x 10^6 kg rises 750 m while traveling a distance of 51.4 km at an average speed of 9.12 m/s. The frictional force is .8 percent of the weight.
Given: acceleration of gravity is 9.8 m/s.
*Find the kinetic energy of the train in MJ.
*Find the total change in its potential energy in J.
*Find the energy dissipated by friction in J.
*Find the power output of the trains engines in MW.
------------------------------------------
On the first part i tried using K = .5mv^2, but that is apparently not the way to do it. I am assuming i have to factor in the work done by friction as well?
That brings me to another question. In trying to find the energy dissipated by friction i did the following:
(mass)(.8 percent)(distance) = Work done by friction
(2.16 x 10^6)(.8/100)(51400) = 8.8819 x 10^8
this is not correct either... so I am puzzled as to what I am doing wrong?
Can anyone point me in the right direction for this problem? Thanks!