The vibrations of a mass of 150 g are simple harmonic. Figure shows the
variation with displacement x of the kinetic energy Ek of
the mass.
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On Figure, draw lines to represent the variation with displacement x of
- potential energy of the vibrating mass (label this line P),
- total energy of the vibrations (label this line T).
- Calculate angular frequency of the vibrations of the mass.
- The oscillations are now subject to damping. Explain what is meant by damping.
Solution:
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- A sensible shape for the line is its inverse of k.e.
- A straight line at 15 mJ, parallel to the x-axis.
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(Maximum) kinetic energy = ½ mv2
= ½mω2a02
=15×10-3=½ × 0.15 × ω2 × (5.0×10-2)2
Angular frequency(ω) = 8.9(4) rad s-1 - Damping refers to the reduction in energy or amplitude within a system or the presence of an external force on a mass.