A ball of mass 0.5kg is thrown at a man of mass 59.5kg standing on roller skates, at a speed of 5 m/s. It is stopped by the man. What is the velocity of the man with the ball?

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?