A copper calorimeter of mass 300 gm contains 500 gm of water at temperature 15°C. A 560 gm block of aluminium at temperature 100°C is dropped in the calorimeter and the temperature is observed to increase to 22.5°C. Find the specific heat capacity of aluminium.

An alpha particle with kinetic energy 12.5 mev makes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude l = p0 b, where p0 is the magnitude of the initial momentum of the alpha particle and b=1.40×10−12 m. (assume that the lead nucleus remains stationary and that it may be treated as a point charge. the atomic number of lead is 82. the alpha particle is a helium nucleus, with atomic number 2.) what is the distance of closest approach?