Two identical fermionic particles with spin s 1/2 are placed in an infinite square well (r) 0, 0 x a such that one particle is in the single particle ground state and the other one is in the oo, otherwise' single particle first excited state. calculate the quantity k (x x2)2 where x1,x2 are the position operators of the two particles. make sure that the spin degree of freedom is taken into account explicitly. how would this quantity change if the two particles were distinguishable

It's because 3 if it was 10 it wouldn't look right do it goes up to 4d

Ithink it is c ,i hope i you

Not what goes around on earth but the universe too.

The figure is missing but we can answer anyway.the correct answer is "releasing the string". in fact, when the person is holding the bow and the arrow, the kinetic energy of the arrow is still zero (because the arrow is not moving). the moment the arrow is released, it acquires a velocity v, so its kinetic energy will become different from zero: where m is the mass of the arrow and v its velocity.  all the other options, instead, do not increase the kinetic energy of the system: -  pulling farther back on the string : this will just increase the elastic potential energy of the system-  holding the arrow higher: this will increase the gravitational potential energy of the system (which is given by u=mgh, where h is the height above the ground)-  decreasing the mass of the arrow: this will decrease the gravitational potential energy of the system (which is given by u=mgh, where m is the mass)