Why don't skateboarders keep flying through the air when they launch off a ramp? * 3 points a. the force of gravity works against the skateboarders' inertia. b. skateboard wheels don't spin fast enough to keep them moving very far. c. the skateboarders have no inertia when they launch off a ramp. d. skateboards do not use newtons to move around the ramps.

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?