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Two identically charged balls are a certain distance apart. The vectors in the diagram below show the magnitude and direction of the electrostatic force on each ball. Suppose the charge on the left ball is now doubled (represented by two plus signs). Which diagram below best represents the forces that now act on the two balls?

A plastic rod is charged up by rubbing a wool cloth, and brought to an initially neutral metallic sphere. It is allowed to touch the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, the rod

An erect object is 50 cm from a concave mirror of radius 60 cm.  The distance of the image from the mirror, in cm, is closest to:

A stone is held at a height h above the ground. A second stone with four times the mass of the first one is held at the same height. The gravitational potential energy of the second stone compared to that of the first stone is

Our course instructors Heath and Chris are pushing on a Ford truck that has stalled. (of course it is a Ford )  They are not able to get it to move. Heath, because he is lazy, quits pushing after 4 min. Chris quits after 8 minutes. Compare the amount of work they each do on the truck. 

Who conducted an experiment on conformity in which people were asked to judge the length of lines?

Luke walks around his busy college campus between classes. He notices smoke coming from the side of the cafeteria, but assumes that someone inside already has called the fire department. What phenomenon does this example illustrate?

Which of the following is the most common explanation of bystander apathy?

Which of the following pairs of variables would illustrate a negative correlation?

About ________ of all participants in Milgram’s study administered the highest level of shock to the learner.