Circular Motion Ball on a String

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SUMMARY

The discussion focuses on the physics of a ball of mass 0.28 kg swinging in a vertical circular path on a string of length 0.85 m. Key equations used include Fnet = ma and ma = (mv^2)/r, leading to calculations of tension in the string at various points in the circular motion. The tension at the top of the circle was calculated to be -11.7 N, while at the horizontal position, it was found to be 5.8 N. The maximum speed of the ball at the bottom, given a tension limit of 23 N, is also derived.

PREREQUISITES
  • Understanding of Newton's Second Law (Fnet = ma)
  • Knowledge of circular motion dynamics (ma = mv^2/r)
  • Ability to draw and interpret free body diagrams
  • Familiarity with tension forces in a string
NEXT STEPS
  • Study the effects of varying mass and string length on tension in circular motion.
  • Learn about the implications of centripetal force in vertical circular motion.
  • Explore the concept of critical speed in circular motion and its relation to tension limits.
  • Investigate real-world applications of circular motion principles in engineering and sports.
USEFUL FOR

Physics students, educators, and anyone interested in understanding the principles of circular motion and tension in strings.

Fredred
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Homework Statement


https://www.dropbox.com/s/slpu1p8jplmxzmy/Screenshot 2014-11-18 20.11.58.png?dl=0

Homework Equations


Fnet = ma
ma = (mv^2)/r

The Attempt at a Solution


ai) Ft up, mg down
/\Ft
I
m
I
\/mg

aii) both down
m
I I
\/mg \/Ft

aiii) Ft right, mg down
m - >Ft
I
\/mg

b) Fnet = ma
-Ft - mg = mv^2/r
Ft = -11.7N (after isolation anf plugging in numbers from problem)

c) Fnet = ma
Ft = mv^2/r
Ft = 5.8N

d) Fnet = ma
Ft + mg = mv^2/r
v = 8.8m/s
 
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Problem Statement
A ball of mass ##m=0.28\text{kg}## swings in a vertical circular path on a string length ##L=0.85\text{kg}##.
[diagram showing ball, string, and a dotted circle indicating the path - pretty much as you think]

(a) Draw force diagrams for the ball when it is (i) at the bottom of the circle, (ii) when it is at the top, and (iii) when the string is horizontal.
(b) If it's speed is ##5.2\text{m/s}## at the top of the circle, what is the tension in the string?
(c) If it's speed is ##4.2\text{m/s}## when the string is horizontal, what is the tension in the string?
(d) If the string breaks when the tension exceeds ##23\text{N}##, what is the maximum speed the ball can have at the bottom?

... that wasn't so hard.

Your answers seem reasonable to me - you should also provide a bit of reasoning with your working when you present them for marking.
 

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