An object of mass m attached to a spring of force constant k oscillates with simple harmonic motion. The maximum displacement from equilibrium is A and the total mechanical energy of the system is E.What is the object's velocity when its potential energy is 2/3E?

Respuesta :

As we know that total energy of SHM is always constant

so here we know that

total energy = Kinetic energy + potential energy

so here we have

potential energy = 2/3E

so we will have kinetic energy as

[tex]KE = E - \frac{2}{3}E[/tex]

now we have

[tex]KE = \frac{1}{3}E[/tex]

now for the speed of the block

[tex]\frac{1}{2} mv^2 = \frac{1}{3}E[/tex]

by solving above equation we have

[tex]v = \sqrt{\frac{2E}{3m}}[/tex]

The object's velocity is √[(kA²)/(3m)]

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Further explanation

Hooke's Law states that the length of a spring is directly proportional to the force acting on the spring.

[tex]\boxed {F = k \times \Delta x}[/tex]

F = Force ( N )

k = Spring Constant ( N/m )

Δx = Extension ( m )

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The formula for finding Young's Modulus is as follows:

[tex]\boxed {E = \frac{F / A}{\Delta x / x_o}}[/tex]

E = Young's Modulus ( N/m² )

F = Force ( N )

A = Cross-Sectional Area ( m² )

Δx = Extension ( m )

x = Initial Length ( m )

Let us now tackle the problem !

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Given:

mass of the object = m

force constant = k

maximum displacement = A

total mechanical energy = E

potential energy = ²/₃E

Unknown:

velocity of the object = v = ?

Solution:

We will use conservation of energy as follows:

[tex]\texttt{Total Mechanical Energy} = E_p + E_k[/tex]

[tex]E = \frac{2}{3}E + \frac{1}{2}mv^2[/tex]

[tex]E - \frac{2}{3}E = \frac{1}{2}mv^2[/tex]

[tex]\frac{1}{3}E = \frac{1}{2}mv^2[/tex]

[tex]\frac{1}{3} (\frac{1}{2}kA^2) = \frac{1}{2}mv^2[/tex]

[tex]\frac{1}{3}kA^2 = mv^2[/tex]

[tex]v^2 = \frac{1}{3}kA^2 \div m[/tex]

[tex]\large {\boxed {v = \sqrt{ \frac{kA^2}{3m}}}}[/tex]

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Learn more

  • Young's modulus : https://brainly.com/question/6864866
  • Young's modulus for aluminum : https://brainly.com/question/7282579
  • Young's modulus of wire : https://brainly.com/question/9755626

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Answer details

Grade: College

Subject: Physics

Chapter: Elasticity

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Keywords: Elasticity , Diameter , Concrete , Column , Load , Compressed , Stretched , Modulus , Young

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