If two macroscopic objects are electrically attracted to each other,

Light having a frequency in vacuum of 6.0 × 1014 Hz enters a liquid of refractive index 2.0. In this liquid, its frequency will be:

X and Y are two uncharged metal spheres on insulating stands, and are in contact with each other. A positively charged rod R is brought close to X as shown in figure 1. Sphere Y is now moved away from X (figure 2). The final charge states of X and Y, respectively, are

A 7.0 μC negative charge is attracted to a large, well-anchored, positive charge. How much kinetic energy does the negatively charged object gain if the potential difference through which it moves is 4 mV?

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?

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. 

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

In England during the Middle Ages an extensive system of canals was used for transportation. Some of these canals crossed over canyons by flowing over bridges (viaducts). Suppose that a heavily loaded barge floating down the a canal crossed over such a waterway bridge. See the pictures of examples of these types of viaducts. Which statement below is most correct.

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

The Robbers Cave experiment showed that