The lenses of the eyeglasses are being cleaned using a nylon cloth. In doing so, which becomes positively charged? Negatively charged? Assume that the lenses are made of glass.

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

The rocket is fired vertically and tracked by the radar station shown. when θ reaches 66°, other corresponding measurements give the values r = 32700 ft, r¨ = 85 ft/sec2, and θ˙ = 0.019 rad/sec. calculate the magnitudes of the velocity and acceleration of the rocket at this position.

"if the pressure acting on an ideal gas at constant temperature is tripled, its volume isa) reduced to one-third.b) increased by a factor of three.c) increased by a factor of two.d) reduced to one-half"