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Edexcel A-Level Physics Damping and Plastic Deformation

Practise Edexcel A-Level Physics damping and plastic deformation by explaining how resistive work removes energy from oscillating systems.

Syllabus
Pearson Edexcel International Advanced Subsidiary/Advanced Level
Course
Physics XPH11/YPH11
Level
A2

Exam points

  • explain damping as energy transfer from the oscillator through work against resistive forces
  • identify damping force as acting opposite to velocity in an oscillating system
  • link ductile plastic deformation or oil dampers to reduced building oscillation amplitude

5.5.153 - Damping and plastic deformation question 1

[Maximum number: 2]

The photograph shows the 60-storey John Hancock Tower in Boston. This is the tallest building in the state of Massachusetts in the USA.

Shortly after the building was completed in 1976 it was discovered that the wind caused the building to have large amplitude oscillations. To reduce the amplitude, a damper system was installed on the 58th floor.

The damper system consists of a lead box supported between springs, as shown below.

When the lead box is displaced, it moves with damped simple harmonic motion.

Figure for Question 5.5.153 - Damping and plastic deformation question 1 — Edexcel A-Level Physics A2
Figure for Question 5.5.153 - Damping and plastic deformation question 1 — Edexcel A-Level Physics A2

As the floor moves, the rollers force oil through holes in the steel plate.
Explain why this reduces the amplitude of oscillation of the building.

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