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Question 20N.2.HL.TZ0.a

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Date November 2020 Marks available [Maximum mark: 1] Reference code 20N.2.HL.TZ0.a
Level HL Paper 2 Time zone TZ0
Command term Outline Question number a Adapted from N/A
a.
[Maximum mark: 1]
20N.2.HL.TZ0.a

A vertical solid cylinder of uniform cross-sectional area A floats in water. The cylinder is partially submerged. When the cylinder floats at rest, a mark is aligned with the water surface. The cylinder is pushed vertically downwards so that the mark is a distance x below the water surface.

At time t=0 the cylinder is released. The resultant vertical force F on the cylinder is related to the displacement x of the mark by

F=-ρAgx

where ρ is the density of water.

Outline why the cylinder performs simple harmonic motion when released.

[1]

Markscheme

the «restoring» force/acceleration is proportional to displacement


Allow use of symbols i.e.
F-x or a-x

Examiners report

This was well answered with candidates gaining credit for answers in words or symbols.