What causes the acceleration of a car's suspension after hitting a road bump?

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SUMMARY

The discussion centers on the acceleration of a car's suspension after hitting a road bump, specifically addressing a quiz question that incorrectly identifies the acceleration-time graph as a straight line. The correct relationship is defined by the equation a = -w²x₀sin(wt), indicating sinusoidal behavior due to simple harmonic motion (SHM). Participants agree that while the acceleration-displacement graph is a straight line with a negative gradient, the acceleration-time graph should not be represented as such, especially considering the effects of damping in real suspensions.

PREREQUISITES
  • Understanding of Simple Harmonic Motion (SHM)
  • Familiarity with the concepts of acceleration and displacement
  • Knowledge of damping effects in mechanical systems
  • Basic proficiency in graphing mathematical functions
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  • Study the principles of Simple Harmonic Motion (SHM) in mechanical systems
  • Learn about the effects of damping on oscillatory motion
  • Explore the mathematical representation of acceleration in SHM
  • Investigate real-world applications of suspension systems in vehicles
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Physics students, automotive engineers, and anyone interested in the dynamics of vehicle suspension systems will benefit from this discussion.

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Homework Statement


Ok, I was stumped by this simple online quiz which asked the variation of acceleration with time of a suspension unit of a car after a road bump which follows SHM. (HC0809)

A. Straight line
B. Ellipse
C. Circle
D. Parabola

The Attempt at a Solution



The answer was supposed to be sinusoidal and the quiz gave the answer as A, straight line but that is obviously wrong since

a=-w^2x

And the correct form is

a=-w^2x_0sinwt

Am i missing something, is the quiz wrong
 
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Was that the exact wording? Maybe there is something you've missed...

Real suspensions also have damping and under particular conditions the oscillation is barely observable... but I don't think a "straight line" would ever be correct for the acceleration.
 
nooooooo... the acceleration-displacement graph is a negative gradient straight line, through origin. and the equation is a = -w^2X0

at least this is what we learn in high school...
 
If you graph acceleration vs. displacement it is indeed a straight line

with a slope of -w^2, as given by his equation a=-w^2*x

However that's not what he was asked for, unless he read the question wrong. Maybe the question made that slip up
 
mda said:
Was that the exact wording? Maybe there is something you've missed...

Real suspensions also have damping and under particular conditions the oscillation is barely observable... but I don't think a "straight line" would ever be correct for the acceleration.

yes there was damping mentioned in the question but I don't see how a straight line could every beformed if the graph was an acceleration time one
 

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