2. If rain is falling vertically downward, and you are running for shelter, should you hold your umbrella vertically, tilted forward, or tilted backward to keep the driest? Please explain.

The slope of a velocity time graph over any interval of time gives the during that interval

The mantle is made up of which structural zones?

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?