Rights to my grandmother in our ancestral property

My Grandfather died 3 years back. He received pension of Rs. 40,000 per month. He also had some ancestral property (Not earned by him) in his name. After his death, my grandmother is get 50% of his pension(i.e., Rs. 20,000). There are two child for my grandparents(1. My father 2. My father's sister). My father's sister died at 1995 ( before getting married). My father died at 2003. I am the only child to my parents. As my grandfather died, my grandmother, my father(late) (My mother as heir to my father) and me(Major) are the heirs. nnQ1. As we belongs to Hindu religion, do my grandmother or my mother has rights to sell our ancestral property?nQ2. My grandfather brought some property in my grandmothers name, do I have any share in it?nQ3. As a widow, can my mother get a share of my deceased grandfather?nQ4. As my grandmother is willing to sell my ancestral property to her brothers, how can I stop it?nQ5. Do we come under HUF(Hindu Undivided Family) law