Tangential Acceleration Problem, UCM

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SUMMARY

The discussion focuses on a physics problem involving tangential acceleration while swinging a ball on a string in a horizontal plane. The key equations identified are the tension formula, Tension = (mv^2)/r, and the radial force equation, F_R = m(a_R). The goal is to derive expressions for the length of the string and the total acceleration as functions of time, initial length (𝑙0), initial speed (𝑣0), and constant tangential acceleration (𝑎_t). The effect of gravity is ignored, simplifying the analysis to purely centripetal and tangential forces.

PREREQUISITES
  • Understanding of circular motion dynamics
  • Familiarity with Newton's second law (F=ma)
  • Knowledge of tension in strings and its relation to centripetal force
  • Basic algebra for manipulating equations
NEXT STEPS
  • Derive the expression for string length as a function of time using the equations provided
  • Explore the concept of centripetal acceleration in detail
  • Learn about the implications of varying tension in strings during circular motion
  • Investigate the effects of tangential acceleration on angular velocity
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and circular motion, as well as educators looking for practical examples of tension and acceleration in dynamic systems.

stark3000
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Homework Statement
A student is swinging a ball on a string overhead in a horizontal plane. The string initially has length 𝑙0 and the ball is moving with an initial speed 𝑣0 . The student decides to see how fast they
can spin the ball, so they begin moving it faster and faster with a constant tangential acceleration 𝑎_t. However, they know that the string is close to breaking, so they decide to keep letting the string get longer and longer in order to keep the tension in the string constant. Find expressions for the length of the string and the total acceleration (magnitude and direction) as a function of time, 𝑙0 , 𝑣0 , and 𝑎_t . You may ignore the effect of gravity on the ball.
Relevant Equations
F_R= m(a_R)
Tension = (mv^2)/r
Tension = m(a_R)
Homework Statement: A student is swinging a ball on a string overhead in a horizontal plane. The string initially has length 𝑙0 and the ball is moving with an initial speed 𝑣0 . The student decides to see how fast they
can spin the ball, so they begin moving it faster and faster with a constant tangential acceleration 𝑎_t. However, they know that the string is close to breaking, so they decide to keep letting the string get longer and longer in order to keep the tension in the string constant. Find expressions for the length of the string and the total acceleration (magnitude and direction) as a function of time, 𝑙0 , 𝑣0 , and 𝑎_t . You may ignore the effect of gravity on the ball.
Homework Equations: F_R= m(a_R)
Tension = (mv^2)/r
Tension = m(a_R)

I will need 2 F net equations.
F_R= m(a_R)
Tension = (mv^2)/r
Tension = m(a_R)
 
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Welcome to the PF. :smile:
stark3000 said:
Tension = (mv^2)/r
It seems like that is the key equation, no? Can you say more about how to use that one equation and the variables they mention to accomplish the goal?
 
berkeman said:
Welcome to the PF. :smile:

It seems like that is the key equation, no? Can you say more about how to use that one equation and the variables they mention to accomplish the goal?
Since I know F=ma, m=F/a. Then, can I plug in this m into the Tension equation to get Tension = (Fv^2/ar)? I am unsure about how to relate the length of the string though.
 

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