The process by which people walk a) requires only a little energy. b) is powered by the body’s surplus heat energy. c) relies on the conversion of chemical energy from food into mechanical energy by muscles. eliminate d) relies on the creation of mechanical energy by muscles, which is transferred into heat energy.

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?