Rotation at an angle - Tether ball (Finding length)

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Homework Help Overview

The discussion revolves around a tether ball problem involving a ball tied to a 3m tall pole, which is swung at a speed of 9.5 m/s, creating an angle of 32° with the vertical. Participants are tasked with finding the length of the string connecting the ball to the pole.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the free body diagram (FBD) and the calculations related to the radius of rotation and string length. Some express confusion regarding the relationship between the calculated radius and the height of the pole.

Discussion Status

There is ongoing exploration of the problem, with participants questioning the validity of their calculations and the problem setup itself. Some guidance is offered regarding the relationship between the radius and the string length, but no consensus has been reached.

Contextual Notes

Participants note discrepancies between the calculated radius and the height of the pole, suggesting potential issues with the problem statement or assumptions made during calculations.

testme
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Homework Statement


A tether ball is a ball at the end of a rope tied to a pole 3m tall. A player whips the ball around with a speed of 9.5 m/s and the string rises to an angle of 32°. Find the length of the string.

length of pole = 3m
v = 9.5
angle θ = 32°

Homework Equations


Fnet = ma



The Attempt at a Solution


I drew the FBD on the diagram itself

http://sadpanda.us/images/857602-GFGQJ1G.jpg

I know I did something wrong because the radius I got is way too big.
 
Last edited by a moderator:
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testme said:

Homework Statement


A tether ball is a ball at the end of a rope tied to a pole 3m tall. A player whips the ball around with a speed of 9.5 m/s and the string rises to an angle of 32°. Find the length of the string.

length of pole = 3m
v = 9.5
angle θ = 32°

Homework Equations


Fnet = ma



The Attempt at a Solution


I drew the FBD on the diagram itself

http://sadpanda.us/images/857602-GFGQJ1G.jpg

I know I did something wrong because the radius I got is way too big.

Actually, your value matches the given information of angle and velocity. It doesn't accord very well with the supposed 3m height of the pole though! And it gets worse when you consider that 14.7m is just the radius of rotation; the string length h will be about twice that!

Looks like a problem with the problem itself, not your work :smile:
 
Last edited by a moderator:
Oh, damn.. I left the next question cause it was the same idea.

So to calculate h ot wpi;d ne

Fx = 14. 7m

14.7 h
----- = ----
sin32 sin 90

h = 27.7 m?
 
testme said:
Oh, damn.. I left the next question cause it was the same idea.

So to calculate h ot wpi;d ne

Fx = 14. 7m

14.7 h
----- = ----
sin32 sin 90

h = 27.7 m?

That looks about right :wink:
 
Thanks a lot, that damn question threw me off.

Anyways, I'm off to bed. G'night everyone who reads this :)
 

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