The atomic number of an element is 22 while its mass number is 48. How many neutrons does the element have

According to social exchange theory, altruistic behaviors benefit the individual who performs them. t/f

Could we see a galaxy that is 20 billion light-years away?

Two masses are connected by a rope that hangs over a pulley as shown below. the pulley is a uniform cylinder of radius 푅=0.381meters and mass 푀=3.1푘푔. initially 푚"is on the ground and 푚#rests 2.5 meters above the ground. if the system is released, use conservation of energy to determine the speed of 푚#just before it strikes the ground. assume the pulley bearing is frictionless.