seeking help finding the initial velocity of a type 3 projectile

AI Thread Summary
The discussion focuses on determining the initial velocity of a type 3 projectile, with the user encountering a negative value for seconds squared in their calculations. They express confusion about whether to take the absolute value of this result. Participants clarify the importance of consistent sign conventions for upward direction, suggesting that the initial velocity in the vertical direction should be negative. The user realizes that the initial velocity should be expressed as negative v1 sin θ. The conversation emphasizes the need for careful attention to sign conventions in projectile motion calculations.
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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