A high-speed drill rotating counterclockwise takes 2.5 s to speed up to 2400 rpm. (a) What is the drill’s angular acceleration?
(b) How many revolutions does it make as it reaches top speed?

Respuesta :

Answer:

(a) Angular acceleration will be [tex]100.53rad/sec^2[/tex]

(b) 50 revolution

Explanation:

We have given time t = 2.5 sec

Initial speed of the drill [tex]\omega _0=0rad/sec[/tex]

Speed after 2.5 sec [tex]=2400rpm=\frac{2\pi \times 2400}{60}=251.327rad/sec[/tex]

From first equation of motion we know that

[tex]\omega =\omega _0+\alpha t[/tex]

[tex]251.327 =0+\alpha \times 2.5[/tex]

[tex]\alpha =100.53rad/sec^2[/tex]

(b) From second equation of motion we know that

[tex]\Theta =\omega _0t+\frac{1}{2}\alpha t^2[/tex]

[tex]\Theta =0\times 2.5+\frac{1}{2}\times 100.53\times  2.5^2=314.16rad=\frac{314.16}{2\pi }=50revolution[/tex]