Oscillations & Traveling Waves: How long is the string?

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SUMMARY

The discussion focuses on calculating the length of a pendulum string using the formula T = 2π√(L/g). A student measures the period of 17 oscillations to be 19.0 seconds, resulting in a calculated period T of 1.118 seconds. The gravitational acceleration g is taken as 9.8 m/s². The student's final calculation mistakenly converts the length to centimeters instead of meters, leading to an incorrect result of 0.3101 cm instead of the correct length of 0.3101 m.

PREREQUISITES
  • Understanding of pendulum motion and oscillation principles
  • Familiarity with the formula T = 2π√(L/g)
  • Basic knowledge of unit conversions, particularly between meters and centimeters
  • Ability to perform calculations involving square roots and algebraic manipulation
NEXT STEPS
  • Review the derivation of the pendulum period formula T = 2π√(L/g)
  • Practice unit conversion techniques, especially between metric units
  • Explore the effects of mass and angle on pendulum motion
  • Investigate the concept of simple harmonic motion in greater detail
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and oscillatory motion, as well as educators looking for examples of pendulum calculations.

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Homework Statement



A 111g ball is tied to a string. It is pulled to an angle of 4.40 Degrees and released to swing as a pendulum. A student with a stopwatch finds that 17 oscillations take 19.0s.
How long is the string?

Homework Equations



T = 2π√(L/g)

The Attempt at a Solution



Period T = 19/17 = 1.118s

g = 9.8m/s2

1.118/2π = √L/g
0.1779 = √L/g
0.0316 = L/g

L = 0.3101cm

This is wrong, someone please tell me my mistake.
 
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