Respuesta :
Answer:
962 rpm.
Explanation:
given,
angular acceleration = 190 rad/s²
initial angular speed = 0 rad/s
final angular speed = 7200 rpm
=[tex]7200\times\dfrac{2\pi}{60}[/tex]
=[tex]754\ rad/s[/tex]
we need to calculate the revolution of disk after 10 s.
time taken to reach the final angular velocity
using equation of angular motion
[tex]\omega_f - \omega_i = \alpha t[/tex]
[tex]754 - 0 =190\times t[/tex]
t = 4 s
rotation of wheel in 4 s
[tex]\theta =\omega_i t+ \dfrac{1}{2}\alpha t[/tex]
[tex]\theta = \dfrac{1}{2}\alpha t^2[/tex]
[tex]\theta = \dfrac{1}{2}\times 190 \times 4^2[/tex]
θ = 1520 rad
[tex]\theta = \dfrac{1520}{2\pi}[/tex]
[tex]\theta =242\ rev[/tex]
now, revolution of the disk in next 6 s
angular velocity is constant
[tex]\omega_f = \dfrac{\theta_f-\theta_i}{t_f-t_i}[/tex]
[tex]754 = \dfrac{\theta_f-1520}{10-4}[/tex]
θ_f = 6044 rad
θ_f = [tex] \dfrac{6044}{2\pi}[/tex]
revolution of the computer hard disk
θ_f = 962 rpm.
total revolution of the computer disk after 10 s is equal to 962 rpm.
