Answer :
Given:
The angular displacement, θ=89.5°
Initial angular velocity, ω₀=47.8 rpm
Final angular velocity, ω=0 rad/s
To find:
The angular acceleration of the wheel.
Explanation:
The angular velocity can be converted to rad/s as,
[tex]\begin{gathered} \omega_0=\frac{47.8\times2\pi}{60} \\ =5\text{ rad/s} \end{gathered}[/tex]The angle is converted into the radians as,
[tex]\begin{gathered} \theta=\frac{89.5\times\pi}{180} \\ =1.56\text{ rad} \end{gathered}[/tex]From the equation of motion,
[tex]\omega^2-\omega^2=2\alpha\theta[/tex]Where α is the angular acceleration of the wheel.
On substituting the known values,
[tex]\begin{gathered} 0^2-5^2=2\times\alpha\times1.56 \\ \implies\alpha=\frac{-5^2}{2\times1.56} \\ =-8.01\text{ rad/s}^2 \end{gathered}[/tex]Final answer:
Thus the angular acceleration of the wheel is -8.01 rad/s²