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Homework Help: Mechanics doubt in Newton's Law of Motion.

  1. Jul 8, 2009 #1
    Question-1. An engine of mass 105 tonnes is coupled to and pulls a carriage of mass 30 tonnes.The resistance to the motion of the engine is 1/100th of its weight.The resistance to the motion of the carriage is 1/150th of its weight.If the tractive force exerted by the engine is 25750 Newton.The tension in the coupling is
    Options- A.4960 N B.496 N C.49.6 N D.4.96 N

    Resistance <- Carriage ->Tension

    Resistance <- Engine -> Tractive force
    .....Tension <-

    I used this method to get the answer but was unable to get so.
    Someone please help.o:)
  2. jcsd
  3. Jul 9, 2009 #2


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    Homework Helper

    The resultant force FR is 25,750N. Tension-Resistance=FR
  4. Jul 9, 2009 #3
    The diagrams look OK.
    Now write Newton's second law for each object.
    You'll have two equations with two unknowns (acceleration and tension).
    Make sure the weight is in teh same units as the traction force.
    For example, for the carriage: 30 tons = 30,000kg. Weight is about 300,000 N . Resistance is 2000 N.
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