Why does a ballistic pendulum have only potential energy at maximum height?

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terryds
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I've watched a video about ballistic pendulum problems.
The illustration is :
5l9e28.jpg


I wonder why the final energy is just a gravity potential energy.
I think there is also a rotational kinetic energy (since it will rotate and oscillate)
Is my thought wrong?
 

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terryds said:
also a rotational kinetic energy
What's the rotational velocity at the "peak" of the pendulum displacement?
 
Bystander said:
What's the rotational velocity at the "peak" of the pendulum displacement?
I'm not quite sure. But, I think it will be v/r
Am I right ?
 
In your sketch, where the maximum displacement from the vertical is indicated to be sixty degrees, how fast is the pendulum moving?
 
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Bystander said:
In your sketch, where the maximum displacement from the vertical is indicated to be sixty degrees, how fast is the pendulum moving?
Do you mean the velocity ?
I think it's 0 m/s since it has reached the amplitude.
Oh yeah.. Thank you for your answer.
I get it now.. Because the velocity is zero, so the rotational kinetic energy is zero !