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~christina~
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[SOLVED] simple POWer question
The electric motor of a model train accelerates the train from rest to 0.620m/s in 21.0ms. Total mass of train 875g.
Find the average power delivered to the train during the acceleration.
[tex]P_{av}= W_{net}/ \Delta t [/tex]
Well..I'm not sure if this is correct...
[tex] W_{net} = K_f- K_i= \Delta K [/tex] ===> I think this is correct but not sure..
using that..
[tex]1/2 mv_f^2 - 1/2 mv_i^2 = 0 [/tex]
vi= 0
[tex] 1/2 mv_f^2= 0 [/tex]
[tex]1/2(.875kg)(0.620m/s)^2 = .1682J[/tex]
P= 0.1682J/ 0.021s= 8.01W====> this seems pretty small but then again it's a model train..is this correct or did I miss something?
I need to know if the way I did the question was correct since they mention acceleration but I'm not sure how would I apply that if I need to at all.
Thank you
Homework Statement
The electric motor of a model train accelerates the train from rest to 0.620m/s in 21.0ms. Total mass of train 875g.
Find the average power delivered to the train during the acceleration.
Homework Equations
[tex]P_{av}= W_{net}/ \Delta t [/tex]
The Attempt at a Solution
Well..I'm not sure if this is correct...
[tex] W_{net} = K_f- K_i= \Delta K [/tex] ===> I think this is correct but not sure..
using that..
[tex]1/2 mv_f^2 - 1/2 mv_i^2 = 0 [/tex]
vi= 0
[tex] 1/2 mv_f^2= 0 [/tex]
[tex]1/2(.875kg)(0.620m/s)^2 = .1682J[/tex]
P= 0.1682J/ 0.021s= 8.01W====> this seems pretty small but then again it's a model train..is this correct or did I miss something?
I need to know if the way I did the question was correct since they mention acceleration but I'm not sure how would I apply that if I need to at all.
Thank you