In the fall of 2002, a group of scientists at los alamos national laboratory determined that the critical mass of neptunium-237 is about 60.0kg. the critical mass of a fissionable material is the minimum amount that must be brought together to start a chain reaction. neptunium-237 has a density of 19.5g/cm3.

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.

An insulated thermos contains 148 g of water at 72.7 ˚c. you put in a 11.7 g ice cube at 0.00 ˚c to form a system of ice + original water. the specific heat of liquid water is 4190 j/kg•k; and the heat of fusion of water is 333 kj/kg. what is the net entropy change of the system from then until the system reaches the final (equilibrium) temperature?

Why does a collision with an airbag cause less damage than a collision with a steering wheel