Little help needed not much but would be appriciated

James Smithson

New member
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Nov 6, 2020
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29
Hello everyone!

I am stuck on a question again, and yet again I feel its my understanding of the English Language letting me down.

I will type up the info and the question and the information I have worked out.


Q7(a) Before puting a tree swing up a programmer models the trajectory a child would follow if it broke at a certain point.

this is his equasion

y= -0.33x^2 + 0.84x + 6 (0≤x≤6)

We are told that x is horizontal distance from the point the swing breaks. and y is the vertical hight of the child from the ground (these are all in meters)

here are some things i think i know:

The y intercept is (0,6) (i think this represents the hight oh the child when the swing breaks ???)
the x intercepts are (5.7,0) and (-3.2,0) (i rounded these to 1 d.p not sure if i was supposed to)


what i need to know and am not sure is:

assuming the ground is flat give a horizontal distance between the start of the childs trajectory and where they would land.

for this I am guessing that it means when the swing breaks (of which i presume it breaks at x=0 ) how far does the child go

does it want me to find the line of symetry for the parabolla and measure the distance to each x intercept ??

completly stuck its been niggling me for a few days.

thank you in advance you are all amazing
 

lev888

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Jan 16, 2018
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Please post a screenshot of the problem.
 

Dr.Peterson

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Nov 12, 2017
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We are told that x is horizontal distance from the point the swing breaks. and y is the vertical hight of the child from the ground (these are all in meters)
assuming the ground is flat give a horizontal distance between the start of the childs trajectory and where they would land.
does it want me to find the line of symetry for the parabolla and measure the distance to each x intercept ??
It is asking for the value of x at the positive x-intercept. It has nothing to do with the line of symmetry, which would locate the highest point of the trajectory.
 

Jomo

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Dec 30, 2014
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10,553
I agree that the y intercept is at (0,6). What I do not understand is how we know that the swing breaks at x=0. I too would like to see a screen shot of the problem.
 

Jomo

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Dec 30, 2014
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10,553
Q7(a) Before putting a tree swing up a programmer models the trajectory a child would follow if it broke at a certain point.
So there is absolutely no reason to assume that the swings breaks when x=0
 

Dr.Peterson

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Nov 12, 2017
Messages
11,507
Q7(a) Before putting a tree swing up a programmer models the trajectory a child would follow if it broke at a certain point.
So there is absolutely no reason to assume that the swings breaks when x=0
Read the question, which I have already quoted in bold; it defines x exactly that way:

We are told that x is horizontal distance from the point the swing breaks.
Yes, it would be better if we had been shown the exact wording in an image, but as it is, we have to trust the asker.

And since this trajectory depends on knowing ahead of time exactly when, where, and at what speed the rope will break, we have to assume that the programmer knows what the "certain point" is. And we aren't told that the swing did actually break at that point; as far as we know this is entirely hypothetical, merely for the sake of checking possible safety issues.

Let it go, until we are shown the problem (and maybe get the address of the publisher to complain to).
 
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