This question is an incomplete question, here is a complete question.
A dentist’s drill starts from rest. After 1.28 s of constant angular acceleration it turns at a rate of 24040 rev/min. Find the drill's angular acceleration in rad/s²
Answer : The angular acceleration of the drill is, [tex]1965.77rad/s^2[/tex]
Explanation :
Formula used for angular acceleration of the drill is:
[tex]a=\frac{\omega_2-\omega_1}{t}[/tex]
where,
a = angular acceleration
[tex]\omega_1[/tex] = initial angular velocity = 0
[tex]\omega_2[/tex] = final angular velocity = [tex]24040rev/min\times \frac{2\pi rad}{rev}\times \frac{1min}{60s}=2516.19rad/s[/tex]
t = time = 1.28 s
Now put all the given values in the above formula, we get:
[tex]a=\frac{(2516.19-0)rad/s}{1.28s}=1965.77rad/s^2[/tex]
Therefore, the angular acceleration of the drill is, [tex]1965.77rad/s^2[/tex]