One of the great dangers to mountain climbers is an avalanche, in which a large mass of snow and ice breaks loose and goes on an essentially frictionless "ride" down a mountainside on a cushion of compressed air. The acceleration of gravity is 9.8 m/s 2 . avalanche µ = 0 347 m 27.5 ◦ If you were on a 27.5 ◦ slope and an avalanche started 347 m up the slope, how much time would you have to get out of the way?

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.