How Do You Solve Kinematics Problems Involving Quadratic Equations?

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Homework Help Overview

The discussion revolves around solving kinematics problems that involve quadratic equations, specifically in the context of projectile motion. Participants are examining the setup and calculations related to an object's motion under gravity.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the use of the quadratic formula in the context of the problem, with one questioning its necessity. There is also a focus on interpreting the problem's requirements regarding the height of the object at a specific point.

Discussion Status

The discussion includes attempts to clarify the problem's setup and the calculations involved. Some participants have provided insights into the interpretation of the problem, while others have expressed uncertainty about the approach taken.

Contextual Notes

There is a mention of the need to determine the height of the object at a specific moment, which may not align with the initial calculations provided. The original poster expresses a desire for assistance in setting up the problem correctly.

Falinox
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Homework Statement


Phyque.jpg

http://i754.photobucket.com/albums/xx183/reddiesel08/Phyque.jpg


2. The attempt at a solution
∆x = ∆x
v₀ + .5(a)(t²) = v(t)
.5(9.8)t² = 35t
4.9t² - 35t = 0 Using the quadratic formula I get
t = 7.95 sec

∆x = v(t)
35(7.95) = 278.25m

Need help setting up and solving the problem, thanks in advance to anyone willing to help :)
 
Last edited by a moderator:
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35/4.9 ≈ 7.143 s.

Why use the quadratic formula? -- although it should give the right answer. (35 ± √(352-0) )/(2(4.9))
 


You've calculated the distance the ball travels from the drop point to the point where it passes superman. The problem however asks you determine how far above the sidewalk the ball is when it passes superman.
 


Thanks everyone! I was able to figure it out.
 

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