Answer:
a. 157 rad/s²
b. 50 revolutions
Explanation:
Initial angular velocity, u = 0
Final v = 3000 rpm = 3000 × 2π/60 rad/s= 314 rad/s
time, t = 2.0 s
a. angular acceleration is given by first equation of rotational motion:
α = (v-u)/t = (314 rad/s-0)/ 2.0 s = 157 rad/s²
b. number of revolutions made before reaching final angular velocity of 3000 rpm. Time taken = 2.0 s.
Use second equation of rotational motion:
θ = u t + 0.5 α t²
⇒ θ = 0 + 0.5 × 157 rad/s² × (2.0 s.)² = 314 rad
⇒n ( number of revolutions) = θ / 2π = 314/ 2π = 50 revolutions