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can initial velocity of an object be negative

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147 views asked Jun 28, 2014 in Physics by faisal-aalum (150 points)

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In Mechanics, Sign (+ or -) is given to indicate direction. So, depending upon which direction you consider as positive, the initial velocity may be positive or negative.

To solve a problem, we take a convenient direction as positive and the direction opposite to it as negative.

 

In the case of vertical motion we may take the upward direction as positive and the downward direction as negative. So, if a stone is thrown vertically upwards, the initial velocity is TAKEN positive and if the stone is thrown downwards from a height, the initial velocity is taken as negative.
answered Jul 12, 2014 by admin (4,920 points)
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Velocity is a vector quantity n sign  of a vector quantity depicts its direction . Its direction depends on the position vector that we assume .Position vector is a function defines the motion of a particle (i.e. a point mass) - its location relative to a given coordinate system at some time t.So as sir said it depends on which direction we consider initially positive .
answered Dec 6, 2014 by vignesh-wesflux (260 points)
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