As a consultant to a theme park, your job is to ensure the safety of the children's rides. You are able to calculate the net force of the roller coasters acting on a 16 kg child over time given a few select data points. At t = 18.48s the position was < 4.53, 2.25, -11.82 > m.
At t = 18.53s the position was <3.5100000000000002, 3.2600000000000002, -11.950000000000001 > m.
At t = 18.580000000000002s the position was <3.99, 3.95, -10.33 > m.

In the first time interval, from 18.48 to 18.53s, what was the average momentum?

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?