Train force physics problem

  • Thread starter mandy9008
  • Start date
  • #1
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Homework Statement


A freight train has a mass of 1.4x107 kg. If the locomotive can exert a constant pull of 6.7x105 N, how long does it take to increase the speed of the train from rest to 84 km/h?


Homework Equations


F=ma
a=v/t


The Attempt at a Solution


I converted 84 km/h into 23.3 m/s.
F=ma
6.7x10^5 N=1.4x10^7 m (a)
a= .047 m/s^2

a=v/t
.047 m/s^2=(23.3 m/s)/t
t=495.7s --> 2.97x10^4 min
 
Last edited:

Answers and Replies

  • #2
rock.freak667
Homework Helper
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That looks correct.
 
  • #3
127
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when I enter it it says that it differs significantly from the correct answer
 
  • #4
rock.freak667
Homework Helper
6,230
31


when I enter it it says that it differs significantly from the correct answer
the t =2.97x104 min is not correct.

t= 495.7 s should be correct.
 
  • #5
127
1


the question asks for time in minutes
 
  • #6
127
1


i converted it and got 8.26 min and got it correct.i don't know what i was thinking converting it before haha thanks
 

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