Aboy picks up a bowling ball. which of the following choices correctly describes the interaction between the boy and the bowling ball? a. the boy exerts an upward force on the ball, and the bowling ball exerts a downward force on the boy. b. both forces are equal in strength. the boy exerts an upward force on the bowling ball, and the bowling ball exerts a downward force on the boy. c. the bowling ball’s force on the boy is the greater force. the boy exerts an upward force on the bowling ball because the ball accelerates. d. the bowling ball does not exert a force on the boy because the boy does not accelerate. e. the boy exerts an upward force on the bowling ball, and the bowling ball exerts a downward force on the boy. f. the boy’s force on the bowling ball is the greater force.

Many machines- including inclined planes such as ramps- increase the strength of the force put into the machine but decrease the distance over which the force is applied.

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?

Which statement best describes copper? a. it has a low resistance and prevents charges from moving freely. b it has a high resistance and allows charges to move freely. c. it has a high resistance and prevents charges from moving freely. d. it has a low resistance and allows charges to move freely