Finding Horizontal Displacement for Spring Cannon Launch

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Homework Help Overview

The problem involves a spring cannon launching a steel ball from a height of 1.2 m at an angle of 35 degrees above the horizontal. Participants are tasked with finding the horizontal displacement of the ball as a function of its launch speed, Vo, and evaluating this function for specific values of Vo. The discussion also includes examining the behavior of the function as Vo approaches zero and as it becomes very large.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the derivation of the horizontal displacement function and the evaluation for specific speeds. There is confusion regarding the limit process for small values of Vo and the implications of the quadratic nature of the equations involved. Some participants suggest inspecting the derived expression for time to simplify the analysis.

Discussion Status

The discussion is ongoing, with participants sharing their approaches and expressions derived for the problem. Some guidance has been offered regarding the Taylor series and the significance of terms in the expression for time. There is a recognition of the complexity of the problem, particularly in parts (d) and (e), and multiple interpretations are being explored.

Contextual Notes

Participants note that they have not yet learned about Taylor series in their calculus class, which may affect their ability to fully engage with some of the suggested approaches. There is also a mention of the ambiguity in expressions and the importance of consistent notation throughout the discussion.

monac
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A spring cannon is located at the edge of a table that is 1.2 m above the floor. A steel ball is launched from the cannon with speed Vo at 35.0 degrees above the horizontal.
(a) Find the horizontal displacement component of the ball tothe point where it lands on the floor as a function of Vo. We writethis function as x(Vo).
Evaluate x for (b) Vo = 0.100 m/s and for
(c) Vo = m/s.
(d) Assume Vo is close to zero but not equal to zero.Show that one term in the answer to part (a) dominates so that thefunction x(Vo) reduces to a simpler form.
(e) If Vo is ver large,what is the approximate form of x(Vo).

I found the answers to a, b, and c. I am thinking of taking a limit on d but the problem is really complicated ... It's a quadratic and with limit laws I would set it equal to 0, but it says it can't be 0. So i am really confused on how to do d and e.
 
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monac said:
A spring cannon is located at the edge of a table that is 1.2 m above the floor. A steel ball is launched from the cannon with speed Vo at 35.0 degrees above the horizontal.
(a) Find the horizontal displacement component of the ball tothe point where it lands on the floor as a function of Vo. We writethis function as x(Vo).
Evaluate x for (b) Vo = 0.100 m/s and for
(c) Vo = m/s.
(d) Assume Vo is close to zero but not equal to zero.Show that one term in the answer to part (a) dominates so that thefunction x(Vo) reduces to a simpler form.
(e) If Vo is ver large,what is the approximate form of x(Vo).

I found the answers to a, b, and c. I am thinking of taking a limit on d but the problem is really complicated ... It's a quadratic and with limit laws I would set it equal to 0, but it says it can't be 0. So i am really confused on how to do d and e.

Why don't you show what you've done so far (to all parts)?

Just a hint, but it'll likely be helpful. Remember the Taylor series (or Binomial theorem) for things like (1+x)-1.
 
it's a long process. I ll just type the main parts of the answers.

(a) x = vicos35t
t = (vi sin35 + √vi^2 sin^2 35 + 23.544) / 9.81
so x = vi cos35 ((vi sin35 + √vi^2 sin^2 35 + 23.544) / 9.81)

for b and c i just had to plug in values for vi and get the x so that was easy.

I have not learned Taylor's series yet in my Calculus II class. :(
 
monac said:
it's a long process. I ll just type the main parts of the answers.

(a) x = vicos35t
t = (vi sin35 + √vi^2 sin^2 35 + 23.544) / 9.81
so x = vi cos35 ((vi sin35 + √vi^2 sin^2 35 + 23.544) / 9.81)

for b and c i just had to plug in values for vi and get the x so that was easy.

I have not learned Taylor's series yet in my Calculus II class. :(

Sorry, your expression is ambiguous. √vi^2 = vi, isn't it?
 
Oh the whole thing is under the square root.
t = (vi sin35 + √(vi^2 sin^2 35 + 23.544)) / 9.81
 
monac said:
I found the answers to a, b, and c. I am thinking of taking a limit on d but the problem is really complicated ... It's a quadratic
I don't think you need any more maths for (d). Just inspect the expression you earlier derived for time but now saying that anything involving Vo is insignificant compared with associated other terms.
 
So imagine that vi = 0?
 
monac said:
So imagine that vi = 0?
For (d), close to 0. (Careful with the notation. The question uses Vo and you seem to have changed it to vi.)
 
In the back of the book, the answer for d was x ~ 0.405 m
 
  • #10
monac said:
In the back of the book, the answer for d was x ~ 0.405 m
Regardless of the speed it's launched, providing it's slow it still travels 0.4m horizontally? That's interesting.

My answer for (d) is XH = þVo
where þ is a fraction that I'll leave you to work out for yourself, but it's between 0.1 and 0.9
 
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