Answer:
-138.23 [tex]rad/s^2[/tex]
Explanation:
The initial angular velocity = 4500 rpm
The final angular velocity = 1200 rpm
1 revolution = 2π radians
1 minute = 60 seconds
So,
[tex]Initial\ velocity=\frac {4500\times 2\pi}{60}\ radians/sec=471.2389\ radians/sec[/tex]
[tex]Final\ velocity=\frac {1200\times 2\pi}{60}\ radians/sec=125.6637\ radians/sec[/tex]
Time = 2.5 seconds
Angular acceleration is:
[tex]\alpha=\frac {\omega_f-\omega_i}{t}[/tex]
[tex]\alpha=\frac {125.6637-471.2389}{2.5}\ rad/s^2[/tex]
Angular acceleration =- 138.23 [tex]rad/s^2[/tex]
