When the negatively charged balloon is brought near the strands of katie's hair, they move to get closer to the balloon, without the balloon actually touching them. this shows that a. particles in the air must be pulling katie's hair toward the balloon. b. katie's hair would move in this way with or without the balloon. c. electric attraction is a force that can act at a distance. d. electric attraction is a force that can only act on contact.

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

What is the molar mass of a gas that has density of 2.054 g/l

The chemical bond connecting one nucleotide with the next one along the nucleic acid chain is called a