Vibrations: A momentum impulse starts a mass into oscillatory motion

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SUMMARY

The discussion centers on the concept of a "sudden momentum impulse" in the context of a mass-spring system as described in Ian Main's book, "Vibrations and Waves." A sudden momentum impulse refers to imparting momentum to the mass at time t=0, transitioning it from rest to motion. The relevant equation of motion for this system is md²x/dt² - kx = 0, where the initial conditions include x(t=0) = x0 and v(t=0) = p1/m. The initial velocity of the mass after the impulse is calculated as v1 = p1/m, confirming the system undergoes simple harmonic oscillation.

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  • Basic principles of oscillatory systems
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Homework Statement
The system shown at rest in fig 1.1(a) could be set into vibration by giving the mass a sudden momentum impulse to the left:by trapping it with a hammer, for example. If the magnitude of the impulse is p1 and its given at time t=0, find (a) the amplitude and (b) the phase constant of the ensuing motion.
Relevant Equations
md^2x/dt^2-kx=0
The fig. 1.1(a) is a mass m attached to a spring that is fixed to a wall. I don't understand what does "a sudden momentum impulse" means. Is it an external force o what?
I imagined that the new equation of motion would be

md^2x/dt^2+dp1/dt-kx=0

md^2x/dt^2+mdv1/dt-kx=0

is this the equation i have to solve?

The problem is from the book Vibrations and Waves in physics from Ian Main.
 
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Zamarripa said:
don't understand what does "a sudden momentum impulse" means
It means going suddenly from rest to moving at some nonzero velocity.
 
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Zamarripa said:
Problem Statement: The system shown at rest in fig 1.1(a) could be set into vibration by giving the mass a sudden momentum impulse to the left:by trapping it with a hammer, for example. If the magnitude of the impulse is p1 and its given at time t=0, find (a) the amplitude and (b) the phase constant of the ensuing motion.
Relevant Equations: md^2x/dt^2-kx=0

The fig. 1.1(a) is a mass m attached to a spring that is fixed to a wall. I don't understand what does "a sudden momentum impulse" means. Is it an external force o what?
I imagined that the new equation of motion would be

md^2x/dt^2+dp1/dt-kx=0

md^2x/dt^2+mdv1/dt-kx=0

is this the equation i have to solve?

The problem is from the book Vibrations and Waves in physics from Ian Main.
The '"sudden momentum impulse" certainly means that the mass is given momentum by a sudden impulse p1 at t=0. Except for the initial moment, there is no external force.
What is the initial velocity of the vibration then?
Check the relevant equation, it is not correct.
 
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ehild said:
The '"sudden momentum impulse" certainly means that the mass is given momentum by a sudden impulse p1 at t=0. Except for the initial moment, there is no external force.
What is the initial velocity of the vibration then?
Check the relevant equation, it is not correct.
The initial velocity is v1=p1/m and the problem is just a simple harmonic oscillation with initial conditions x(t=0)=x0, v(t=0)=v1?
 
Zamarripa said:
The initial velocity is v1=p1/m and the problem is just a simple harmonic oscillation with initial conditions x(t=0)=x0, v(t=0)=v1?
Yes.
 
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