A gymnast whose weight is 5 10 N hangs from the middle of a bar supported by two vertical strands of rope. What is the tension in each strand? A. 765 N
B. 0 N
C. 1020 N
D. 510 N
E. 255 N

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.