Which object is in static equilibrium?

a rolling ball that has a net force acting on it
a cruising car that has no net force acting on it
a book that has no net force acting on it and is sitting on a table
a vase that has a net force acting on it and is sitting on a shelf

Asap and show ! a 14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.

What would be the result of an alpha particle coming into a magnetic field? a) the alpha particle will stop moving. b) the alpha particle will reverse its direction. c) the alpha particle will be deflected in a curve path. d) the alpha particle will continue to travel in a straight line.

Of is j/kg·k. if a 2.6 kg of isk to k, is ?