Show that the speed of the object is constant

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SUMMARY

The discussion centers on demonstrating that an object's speed remains constant when its acceleration vector is always perpendicular to its velocity vector. The key equation used is the dot product, where the condition for perpendicularity is expressed as \(\vec{v} \cdot \vec{a} = 0\). This leads to the conclusion that the rate of change of the speed, represented as \(\frac{d}{dt} ||\vec{v}||\), is zero, confirming that speed does not change under these conditions.

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Homework Statement


Suppose an object moves in such a way that its acceleration vector is always perpendicular to its velocity vector. Show that speed of the object is constant.


Homework Equations


For two vectors to be perpendicular: A\bulletB=0
Speed of the object = ||Velocity Vector||


The Attempt at a Solution


I have no idea how to approach this question. How can the speed of the object affect whether or not the acceleration vector is perpendicular to the velocity vector?
 
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Dukefool said:

Homework Statement


Suppose an object moves in such a way that its acceleration vector is always perpendicular to its velocity vector. Show that speed of the object is constant.

Homework Equations


For two vectors to be perpendicular: A\bulletB=0
Speed of the object = ||Velocity Vector||

The Attempt at a Solution


I have no idea how to approach this question. How can the speed of the object affect whether or not the acceleration vector is perpendicular to the velocity vector?
\displaystyle \vec{a}=\frac{d\vec{v}}{dt}

So, what if \displaystyle \vec{v}\cdot\vec{a}=0\ ?

Then \displaystyle \vec{v}\cdot\frac{d\vec{v}}{dt}=0\ .

Can you write the left-hand side of that last expression in a different way?
 

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