Differentiate y component of velocity wrt time

AI Thread Summary
The discussion focuses on differentiating the y-component of velocity in projectile motion with respect to time. It confirms that the derivative of the y-component of velocity, dv/dt, equals -g, indicating the acceleration due to gravity acts downward. Participants clarify that the sign of -g is based on the conventional upward orientation of the coordinate system. The conversation emphasizes the importance of understanding coordinate systems in physics problems. Overall, the differentiation process and its implications in projectile motion are clearly outlined.
ZedCar
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Homework Statement


A ball is thrown with an angle of 45 degrees to the horizontal by a person standing on the ground.

The y-component of the velocity of ball in projectile motion is differentiated with respect to time. i.e. dv/dt of the y-component of velocity.

Homework Equations


The Attempt at a Solution



Does this equal -g? (not g)
 
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Hi ZedCar! :smile:
ZedCar said:
…. i.e. dv/dt of the y-component of velocity.

you mean,

d/dt of the y-component of velocity

or the y-component of dv/dt

or d/dt of vy :wink:
Does this equal -g? (not g)

yes :smile:
 
But isn't the sign supposed to depend on the orientation of the coordinate system?
 
failexam said:
But isn't the sign supposed to depend on the orientation of the coordinate system?

yes, but i think we can safely assume that the y direction mentioned in the question is the usual upward one :smile:
 
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