contestada

A frictionless block of mass 2.10 kg is attached to an ideal spring with force constant 250 N/m . At t=0 the spring is neither stretched nor compressed and the block is moving in the negative direction at a speed of 13.0 m/s .
Part AFind the amplitude.SubmitMy AnswersGive UpPart BFind the phase angle.

Respuesta :

Answer:

Explanation:

Given

mass of block [tex]m=2.12 kg[/tex]

spring constant [tex]k=250 n/m[/tex]

speed of block at t=0 is [tex]v=13 m/s[/tex]

natural Frequency of oscillation [tex]\omega _n=\sqrt{\frac{k}{m}}[/tex]

[tex]\omega _n=\sqrt{\frac{k}{m}}[/tex]

[tex]\omega _n=\sqrt{\frac{250}{2.12}}[/tex]

[tex]\omega _n=\sqrt{117.92}[/tex]

[tex]\omega _n=10.85 rad/s[/tex]

Suppose [tex]x=A\cos (\omega _nt+\phi )[/tex]

where [tex]\phi =Phase\ difference[/tex]

at t=0 spring is neither compressed

Amplitude is given by

[tex]A=\sqrt{x^2+(\frac{v}{\omega })^2}[/tex]

at t=0 x=0 i.e. at mean Position

[tex]A=\sqrt{0+(1.198)^2}[/tex]

[tex]A=1.198 m[/tex]

at [tex]t=0[/tex]

[tex]x=A\cos (\omega _nt+\phi )[/tex]

[tex]x=1.198\cos (0+\phi )[/tex]

[tex]0=\cos (\phi )[/tex]

therefore [tex]\phi =\frac{\pi }{2}[/tex]