If the atomic number of an element is 8 and its mass number is 20, how many neutrons are in the atom's nucleus?

Calculate the kinetic energy of earth due to its spinning about its axis. krot = j compare your answer with the kinetic energy of the orbital motion of earth's center of mass about the sun. assume earth to be a homogeneous sphere of mass 6.00 1024 kg and radius 6.40 106 m. the radius of earth's orbit is 1.50 1011 m.

Agymnast dismounts off the uneven bars in a tuck position with a radius of 0.3m (assume she is a solid sphere) and an angular velocity of 2rev/s. during the dismount she stretches out into the straight position, with a length of 1.5m, (assume she is a uniform rod through the center) for her landing. the gymnast has a mass of 50kg. what is her angular velocity in the straight position?

What are two different ways you could find the value of a? explain these methods.