Answer
The kinetic energy of the system is $~~880~J$
Work Step by Step
In part (d), we found that the final angular speed is $~\omega_f = 8.4~rad/s$
In part (d), we found that the final rotational inertia of the system is $~I_f = 25~kg~m^2$
We can find the kinetic energy of the system:
$K = \frac{1}{2}I_f~\omega_f^2$
$K = \frac{1}{2}(25~kg~m^2)(8.4~rad/s)^2$
$K = 880~J$
The kinetic energy of the system is $~~880~J$.
