According to the law of conservation of mechanical energy, you will find that

Before the collision, the angular velocity of the bar is ω degrees.

conservation of momentum

jω= jω'+v . m . l

( 1)

,

Ω'-Find the angular velocity after rod collision.

V- the velocity of the object after collision

In a completely elastic collision, the kinetic energy should remain unchanged before and after the collision.

J.ω^2/2=J.ω'^2/2+mv^2/2

(2)

( 1)

(2) simultaneous solvability

ω'

and

v

Getting block m

:a=-μ mg/m =-μ g

,

Uniform acceleration v-s formula

0-v^2=2a.s

-& gt； The block glides over the distance of the genus.

s=-v^2/(2a)=v^2/(2μg)