A ball of mass 0.2kg is dropped from rest from the top of 45m tall building. What is the velocity of the ball?​

Which pair below describes isotopes of the same element? a) an atom with 6 protons and 8 neutrons - an atom with 8 protons and 6 neutrons b) an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons c) an atom with 8 protons and 8 neutrons - an atom with 7 protons and 8 neutrons d) an atom with 7 protons and 6 neutrons - an atom with 6 protons and 6 neutrons