Robert decides it would be fun to jump off of the back of his canoe while fishing in the lake one day. after he jumps out of the canoe, he notices that the canoe is no longer in the same place from where he jumped. which statement best explains why this occurred? a) an object at rest stays at rest. reactivate b) an object in motion stays in motion. c) for every action, there is an equal and opposite reaction. d) the acceleration of an object is determined by the weight of the object and the force applied to it.

Chapter 23, problem 075 the figure shows a geiger counter, a device used to detect ionizing radiation (radiation that causes ionization of atoms). the counter consists of a thin, positively charged central wire surrounded by a concentric, circular, conducting cylindrical shell with an equal negative charge. thus, a strong radial electric field is set up inside the shell. the shell contains a low-pressure inert gas. a particle of radiation entering the device through the shell wall ionizes a few of the gas atoms. the resulting free electrons (e) are drawn to the positive wire. however, the electric field is so intense that, between collisions with gas atoms, the free electrons gain energy sufficient to ionize these atoms also. more free electrons are thereby created, and the process is repeated until the electrons reach the wire. the resulting "avalanche" of electrons is collected by the wire, generating a signal that is used to record the passage of the original particle of radiation. suppose the radius of the central wire is 24 âµm, the inner radius of the shell 2.3 cm, and the length of the shell 14 cm. if the electric field at the shell's inner wall is 2.8 ă— 104 n/c, what is the total positive charge on the central wire?

Anybody wanna ? (picture included? )

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.