2D Reflect(bounce) With Rotation

Hello,

I am new in Unity. I want to bounce a stick.Stick jumps but rotation is ignored. How can reflect (bounce) using rotation?

   private void OnCollisionEnter2D(Collision2D collision)
     {
     Vector2 ground = collision.contacts[0].normal;
     var dir = Vector2.Reflect(rb.velocity.normalized, ground).normalized;
     rb.velocity = dir.normalized * speed 
     }

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