The turbine and associated rotating parts of a jet engine have a total moment of inertia of 23 kg m2. The turbine is accelerated uniformly from rest to an angular speed of 140 rad/s in a time of 27 s.

Question

(a) Find the angular acceleration.


(b) Find the net torque required.


(c) Find the angle turned through in 27 s.


(d) Find the work done by the net torque.


(e) Find the kinetic energy of the turbine at the end of the 27 s.

Answer 1

You should not have to ask this question. I am sure exactly how to do it is in your text book.

(a) alpha = change in speed (140)/change in time (27)

(b) Torque = I alpha = 23 * alpha

(c) A = 0 + 0 t + (1/2) alpha t^2

(d)and (e) work done = change in kinetic energy
= (1/2) I w^2
where w = alpha t = 27 alpha