9. Justin stands still at a bus stop for 20 minutes. he has a mass of 45 kg. How much work was done while he was standing there

Because light travels in a straight line and casts a shadow, isaac newton hypothesized that light is

If forces acting on an object are unbalanced. true or false

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?