According to the scientific definition, which is not an example of work?
a. opening the refrigerator door
b. pushing against a car without moving it
c. lifting a book off a desk
d. pulling socks out of the dryer

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?