A wheel initially has an angular velocity of 18 rad/s, but it is slowing at a constant rate of 2 rad/s 2 . By the time it stops, it will have turned through approximately how many revolutions?

Respuesta :

Answer:13 revolution

Step-by-step explanation:

Given  data

Wheel initial angular velocity[tex]\left ( \omega \right ) [/tex]=18 rad/s

Contant angular deaaceleration[tex]\left ( \alpha \right )[/tex]=2[tex]rad/s^2[/tex]

Time required to stop wheel completely=t sec

[tex]\omega =\omega_0 + \aplha t[/tex]

0 =18 +[tex]\left ( -2\right )t[/tex]

t=9 sec

Therefore angle turn in 9 sec

[tex]\theta [/tex]=[tex]\omega_{0} t[/tex]+[tex]\frac{1}{2}[/tex][tex]\left ( \alpha\right )t^{2}[/tex]

[tex]\theta [/tex]=[tex]18\times 9[/tex]+[tex]\frac{1}{2}[/tex][tex]\left ( -2\right )\left ( 9\right )^2[/tex]

[tex]\theta [/tex]=81rad

therefore no of turns(n) =[tex]\frac{81}{2\times \pi}[/tex]

n=12.889[tex]\approx [/tex]13 revolution

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