My rounding is off - can anyone try this?

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Homework Help Overview

The discussion revolves around a projectile motion problem where the original poster is struggling with rounding errors in their calculations. The context involves determining the height of a projectile at a specific point, which requires the use of a quadratic equation related to the motion of the projectile.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the need to identify the correct point of descent for the projectile, questioning the original poster's use of equations and rounding methods. There are inquiries about the specific equation being used and the value of gravitational acceleration. Some suggest recalculating without rounding to improve accuracy.

Discussion Status

The discussion is ongoing, with participants providing guidance on recalculating the problem and questioning the clarity of the original poster's approach. There is no explicit consensus on the correct method, but several participants are exploring the implications of rounding and the equations involved.

Contextual Notes

The original poster is under time constraints, needing to submit their work shortly, and has expressed frustration with the responses received so far. There is a mention of specific values and assumptions that may not have been clearly communicated in the initial post.

jaytm2291
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There are two points where the ball is at 6.3 height. You have to choose the point where the ball descends: the higher root of the quadratic equation.

ehild
 
What equation?
 
jaytm2291 said:
What equation?

The equation between y and x of a projectile.

ehild
 
I'm sorry you aren't being very clear. I didn't use a quadratic equation but I would like to. THis is due in about an hr. I have one try left. Please help me out instead of just giving me one word answers. Thanks.
 
What value of g you have used? And do not round v0 when you calculate this distance. I am not allowed to give the result, sorry, but I would say that your value is correct within 2 percent. My one is a bit higher than 2.4 m.

ehild
 
Last edited:
So I would have:

y=.33 tan(x)-4.9 (.33/(18.1 cos(x))^2

?
 
If your rounding is off, why don't you go through your calculations from the start and not round anything, at all. That way you will get the most accurate answer possible.

All you're asking here is for someone to do that for you, which they may do, but they can't give you the answer so it serves no purpose aside from to say your answer is wrong (which you know from the test).

You can easily go through it again from the start without rounding in well under an hour.

As it stands, I can go through it but my response will be no different to ehild. I can only tell you that your answer is incorrect and roughly how far out you are.

Jared
 
My calculations don't work for the real answer, but they do for the practice answer.
 
  • #10
jaytm2291 said:
My calculations don't work for the real answer, but they do for the practice answer.

In your original post you only mention your rounding is off, nothing is mentioned about the calculations. You should have been far more specific in the original post to stand a better chance at getting your required response.

From reading the OP, everyone will give the same response as per ehild and what I said in my previous post.

Jared
 
  • #11
jaytm2291 said:
So I would have:

y=.33 tan(x)-4.9 (.33/(18.1 cos(x))^2

?

This equation is wrong. Find the proper equation between the x and y coordinates of the projectile. The argument of the tangent and cosine is the launch angle with respect to the horizontal. It is given, 53 degrees. Why do you consider it unknown?

ehild
 

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