A critical mass is needed for a chain reaction because A) if ...

[natalie2426]

A critical mass is needed for a chain reaction because
 
  A) if the mass is too small the temperature achieved during fission will be too low to sustain the reaction.
  B) if the mass is too large, the temperature will get too high and the entire mass will blow up without fissioning.
  C) if the mass is too large, the density will be too high to sustain a chain reaction.
  D) if the mass is too small, too many neutrons will leak out without causing fission.
  E) if the mass is too small, there will not be enough uranium to start the reaction.

Question 2

In a police ballistics test, a 10.0-g bullet moving at 300 m/s is fired into a 1.00-kg block at rest. The bullet goes through the block almost instantaneously and emerges with 50.0 of its original speed.
 
  What is the speed of the block just after the bullet emerges? A) 1.50 m/s
  B) 2.97 m/s
  C) 3.00 m/s
  D) 273 m/s

[iceage]

Answer to Question 1

D

Answer to Question 2

A

[natalie2426]

Gracias!

[adf223]

Excellent