When all the spheres on earth interact, that is known as

Which two objects have the greatest gravitational force acting between them

Will you chech and finish these for me, because i am stumped with them.

Determine the fraction of the magnitude of kinetic energy lost by a neutron (m1 = 1.01 u) when it collides head-on and elastically with a target particle at rest which is 21h (heavy hydrogen, m = 2.01 u).