Distance Lifted by Car Suspensions in Earthquake

  • Thread starter Thread starter lany
  • Start date Start date
  • Tags Tags
    Car Earthquake
AI Thread Summary
The discussion revolves around calculating the distance a car's undamaged suspensions lift the body when four passengers exit during an earthquake. The car, with a total mass of 1419.6 kg, experiences vertical oscillations at a frequency of 1.8 Hz, resulting in maximum amplitude of vibration. The user attempts to apply concepts of forced and simple harmonic oscillation to derive the displacement of the car body. They express confusion over the equations and calculations, particularly regarding the relationship between acceleration, displacement, and the effects of the passengers exiting quickly. The user seeks clarification and hints to simplify the problem-solving process.
lany
Messages
5
Reaction score
0

Homework Statement


4people with uniform mass= 72.4kg
car mass= 1130kg
earthquake strikes,car is stationary.
vertical oscillations make car bonuce on suspensions.
when frequency= 1.8 Hz car exhibits maximum Amplitude of vibration.
Earthquake over,4 people leave the car quickly,what distance does the cars undamaged suspensions lift the car body as the people get out?



Homework Equations


sorry I am new to this i don't understand what this section wants


The Attempt at a Solution



i took this as a forced oscillation and as a simple harmonic oscillation.
total mass = 1419.6 kg
Velcoity = 3.6*pi*Amax (Amax=max amplitude)
this comes from Vel=omega*Amax
omega=2*pi*Frequency

Acceleration = 2Amax/period
i don't know i thought this one up...
as max displacement= Amax + A max
and time taken => period = 1/frequency...

Acc= 3.6 Amax

x=displacement of car body by suspension...

x=Asin(omega*t)
x'=A*omega*sin(omega*t)
x''= - omega^2 *(x)

...
3,6Amax = -(2*pi*1.8)^2 *x

=> x= - 0.028*Amax

my head is exploding someone please give me some hint...i have an awful feeling that this could be a lot easier...

fiendishly difficult differential equations are suspected but I'm not sure how to relate everything...its kinda late here in Ireland!please have some pity...
 
Physics news on Phys.org


I just thought that since they left the car quickly then t must be tending towards zero...?
right track?
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Difference between resonance in undamped vs damped mass-spring-dashpot
Replies
17
Views
2K
Foucault Pendulum at the North Pole
Replies
9
Views
2K
Oscillations car suspension help
Replies
4
Views
2K
Damped oscillation of a car on a road: velocity calculation
Replies
11
Views
2K
Oscillatory motion and Hooke's law
Replies
1
Views
3K
Simple Harmonic Motion of an earthquake
Replies
4
Views
8K
The Importance of Damping in Simple Harmonic Motion Explained
Replies
1
Views
3K
Archived Time for a trampoline jumper to lift off?
Replies
1
Views
2K
Intuitive Explanation of Mass-on-Spring Oscillator Frequency
Replies
20
Views
4K
Oscillating springs in relativistic time frame
Replies
11
Views
2K

Hot Threads

Recent Insights

Back
Top