Answer
(a) decrease
(b) $5.5~J$
(c) $0.3~J$
Work Step by Step
(a) We know that the kinetic energy decreases because some of the energy is dissipated during the collision.
(b) We can find the initial kinetic energy of the system as follows:
$K.E_i=\frac{1}{2}mv_i^2$
We plug in the known values to obtain:
$K.E_i=\frac{1}{2}(1.5Kg)(2.7m/s)^2$
$K.E_i=5.5J$
(c) The final kinetic energy is given as
$K.E_f=\frac{1}{2}I\omega^2$
We plug in the known values to obtain:
$K.E_f=\frac{1}{2}(4.1Kgm^2+(1.5Kg)(0.4m)^2)(0.373rad/s)^2$
$K.E_f=0.3J$
