An engine pulls a car of mass 1500kg on a level road at constant speed of 5m/s.If the frictional force is 500N,what power does the engine generate?

Dear Student!!

As power is equal to,

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F=m x a

500N=1500kg x a

a=500N/1500kg  = a=0.3ms-2

 

Third law of motion:

2as=v2-u2

2(o.3)s=25

s=25/0.6

s=41m  (appx)

Now  w= f x s

  = 500x 41

  = 20500joules  (appx)

second law of motion:

  s=ut+1/2at2

  41=1/2 (o.3)(t2)

  0.3(t2)=82

  t2=82/0.3

  t2= 273

  t=16.5s  (appx)

 

now  power=work done/ time taken

  p=20500/16.5

  power=1242Js-1  (appx)

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NO YOUR ANSWER IS WRONG ,THE CORRECT ANSWER IS 7.5KW .BUT I DON'T NO THE SOLUTION!!!!

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