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1 Oct 2008 15:23:00 IST

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a person is walking 1km now what will be the friction exerted by the ground???

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a person is walking 1km now what will be the friction exerted by the ground???

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Blazing goIITian

Joined: 1 Apr 2007

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1 Oct 2008 16:12:55 IST

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person walks 2 km or 0.0000004 km..or 400000km ..it doesn't matter...friction cannot be determined..(friction coefficient is variant and different )

but yes work till then can be said to be approximately zero...

10904him

Hot goIITian

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1 Oct 2008 16:49:16 IST

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No the friction will be zero because considering a system moving with constant velocity f self adjusts to zero.In actual fact when the person walking applies force on the ground to move there is an opposing friction otherwise not.But we can approximate the condition to be zero friction and consider man just a mass moving at constant velocity.

HEMANT BHARDWAJ

Blazing goIITian

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1 Oct 2008 16:57:07 IST

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it is not given that wether he travelled 1Km distance by constant speed or non uniform speed. but since change in linear momentum of man is zero(if man comes to rest after waiking this distanceand was initially at rest) then avg friction force will be zero since friction force is the only external force which can act on the man in horizontan direction.

HEMANT BHARDWAJ

Blazing goIITian

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1 Oct 2008 16:59:21 IST

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using very general formula of impulse

impulse=change in momentum=avg Force * time

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Scorching goIITian

Joined: 26 Jul 2008

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2 Oct 2008 07:38:41 IST

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if this question is from h c verma then consider general spped of humans.i too got the doubt but my sir said me to take avg speed of 15km/hr and friction co efficient in general conditions as if u like

Blazing goIITian

Joined: 17 Jul 2008

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2 Oct 2008 08:23:31 IST

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In these cases, take friction coeff. to be 0.5 and assume him to be moving with a consant speed.

@INDIAN_ARMY

Its even practical that we walk with uniform velocity, we don't increase our speed with time while walking. So speed is to be taken uniform by default.

And yes friction isn't the only force active along the ground, the force applied by the man backwrads is also acting along the ground.So, U can't equate friction to 0.

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