Bài 8:
a)
Bài 9
| [tex]\Delta \varphi =\omega\Delta t=60\pi \Rightarrow x=Acos\frac{\pi}{4}=\sqrt{2}(cm)[/tex]
[tex]\Rightarrow v=-\omega\sqrt{A^2-x^2}=-5\pi\sqrt{2}(cm/s)[/tex] |
| [tex]\Delta \varphi =\omega\Delta t=6172\pi+\frac{\pi}{2} \Rightarrow x=-Acos\alpha=-\sqrt{2}(cm)[/tex]
[tex]\Rightarrow v=-\omega\sqrt{A^2-x^2}=-5\pi\sqrt{2}(cm/s)[/tex] |
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Bài 10:
| [tex]\Delta \varphi =\omega\Delta t=60\pi[/tex]
[tex]\Rightarrow N=60.1=60[/tex] |
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Bài 11:
| t=1s
[tex]\Delta \varphi =\omega\Delta t=\pi\Rightarrow s_1=2A=10(cm)[/tex]
|
| t=13,9s
[tex]\Delta \varphi =\omega\Delta t=12\pi+\pi+0,9\pi[/tex]
[tex]\Rightarrow s_2=12.2A+2A+A(1-cos\alpha)\approx 130,54(cm)[/tex] |
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[tex]\Rightarrow \Delta s=s_2-s_1 =120,55(cm)[/tex]
Bài 12:
[tex]\Delta\varphi=\omega\Delta t=\pi+0,4\pi[/tex]
[tex]s_{max}=2A+2A.sin\frac{0,4\pi}{2}\approx 12,7(cm)[/tex]
[tex]s_{min}=2A+2A(1-cos\frac{0,4\pi}{2})\approx 9,53(cm)[/tex]
Bài 13:
| [tex]s=2019,6=50.4A+19,6[/tex]
[tex]\Delta \varphi= 50.2\pi+\frac{2\pi}{3}+\alpha[/tex]
[tex]\Delta t=\frac{\Delta\varphi}{\omega}\approx 101(s)[/tex] |
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Bài 14:
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[tex]\Delta \varphi=4\pi[/tex]
[tex]\Rightarrow \Delta t=\frac{\Delta\varphi}{\omega}=1(s)[/tex] |
| [tex]2018=2016+2[/tex]
[tex]\Delta \varphi=\frac{2016}{2}.2\pi+\pi[/tex]
[tex]\Rightarrow \Delta t=\frac{\Delta\varphi}{\omega}=504,25(s)[/tex] |
|
[tex]2019=2018+1[/tex]
[tex]\Delta \varphi=\frac{2018}{2}.2\pi+\frac{2\pi}{3}[/tex]
[tex]\Rightarrow \Delta t=\frac{\Delta\varphi}{\omega}=504,67(s)[/tex] | |
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