seeking help finding the initial velocity of a type 3 projectile

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Homework Help Overview

The discussion revolves around determining the initial velocity of a type 3 projectile, with participants exploring the implications of their chosen coordinate system and the signs associated with velocity components.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are examining the signs used for the upward direction and how this affects the calculation of initial velocity. There is a specific focus on whether to take the absolute value of a negative result and the implications of using negative values for velocity components.

Discussion Status

The discussion is active, with participants questioning the assumptions regarding directionality and the signs of the initial velocity. Some guidance has been offered regarding the signs used, but no consensus has been reached on the correct approach.

Contextual Notes

There appears to be confusion regarding the coordinate system and the assignment of signs for upward motion, which may affect the calculations being discussed.

pluralangel
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Homework Statement
a projectile is launched 40° above the horizontal and lands a vertical distance of 0.943 m below and a horizontal distance of 2.4 m away; what is the initial velocity of the projectile?
Relevant Equations
vy = v sin θ
vx = v cos θ
v = Δd / Δt (constant velocity)
Δd = v1 Δt + 0.5a Δt^2 (uniform acceleration)
hi, so I've been trying to find the initial velocity of this projectile; but i ended up getting a negative value for seconds squared. I've gone over my solution multiple times but don't see where i went wrong. alternatively, was i supposed to take the absolute value of seconds squared?

thanks in advance for any help : )

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Which sign are you using for the upwards direction?
 
PeroK said:
Which sign are you using for the upwards direction?
up would be negative
 
pluralangel said:
up would be negative

And your initial velocity in the ##y## direction is?
 
PeroK said:
And your initial velocity in the ##y## direction is?
ooh, it would have to be negative v1 sin θ ?
 
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thanks so much ^_^
 

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