You place a mass of 250 grams on the measurement tray of a triple beam balance and then set the rider on the 500 gram beam to the 200 gram mark (the other riders are set to 0 grams). which of the following statements is true?
a. the pointer will be above the zero mark.
b. the pointer will be below the zero mark.
c. the pointer will be lined up with the zero mark.
d. the pointer will move up and down once per second.

Your physics assignment is to figure out a way to use electricity to launch a small 6.0-cm-long plastic drink stirrer. you decide that you'll charge the little plastic rod by rubbing it with fur, then hold it near a long, charged wire, as shown in figure p23.56 . when you let go, the electric force of the wire on the plastic rod will shoot it away. suppose you can uniformly charge the plastic stirrer to 10 nc and that the linear charge density of the long wire is 1.0 x10-7 c/m. what is the net electric force on the plastic stirrer if the end closest to the wire is 2.0 cm away?