How can acceleration be perpendicular to velocity at any given time?

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Acceleration can be perpendicular to velocity when an object moves in a circular path, as the velocity vector is tangent to the circle while acceleration points toward the center. When an object is released from circular motion, it will continue in a straight line in the direction of its velocity at that moment. The change in velocity can be analyzed using vector subtraction, and instantaneous acceleration can be determined by considering an infinitesimally small angular separation. In uniform circular motion, the speed remains constant, but the direction changes, resulting in a centripetal acceleration directed radially inward. Thus, the relationship between acceleration and velocity in circular motion illustrates how they can be perpendicular at any given time.
tatiana
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How can acceleration be perpendicular to velocity at any given time?
Is it because when ther is a circular path, there can be lines drawn tanget to the circular path that it follows? I don't understand!
 
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If you suddenly release an object rotating around a circle, which direction does it go?
 
When you make an object twirl on the end of a string, you're always pulling aren't you?

To pull something is to cause acceleration! (unless the object pulled on is fixed)
 
The direction of the velocity at any point is tangential to the circle at that point.To find the change of velocity between two points you can perform a vector subtraction of the velocities at the two points and to find the average acceleration between the points divide the velocity change by the time.To find the instantaneous acceleration consider the limit where the angular separation between the points approaches zero.You will find that the direction of the acceleration is towards the centre of the circle.
 
tatiana said:
How can acceleration be perpendicular to velocity at any given time?
Is it because when ther is a circular path, there can be lines drawn tanget to the circular path that it follows? I don't understand!

This is because the velocity at a particular instant is directed along tangent at that point while the acceleration is always directed towards the center of the circle. Clearly these two are perpendicular to each other.
 
Remember that velocity is a vector quantity and acceleration is the time rate of change of velocity. Since velocity is a vector it has both direction and magnitude; therefore a change in velocity can be a change in magnitude (speed) or a change in direction.

You can break any acceleration vector into components along the line of velocity and perpendicular to the velocity. The component of acceleration along the direction of velocity changes the speed, and the perpendicular component changes the direction.
 
tatiana said:
How can acceleration be perpendicular to velocity at any given time?
Is it because when ther is a circular path, there can be lines drawn tanget to the circular path that it follows? I don't understand!
I could put it yet another way:
Acceleration is rate of change of velocity. Velocity is speed and direction. If the speed is constant (it's just going round and round), it is only the direction that is changing for a circular path. The change of direction is along a radius so that is the direction where the acceleration is.
Also, if the string is totally flexible, then it can ONLY pull along a radius. That means that the only possible direction of acceleration must be along a radius as it's the only direction that any force is acting.
 

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