Common transparent tape can becomes charged when pulled from a dispenser. if two identical pieces of tape are pulled from two freshly loaded tape dispensers so that they have the same charge and one piece is placed above another, the repulsive force can be great enough to support the top piece’s weight. calculate the magnitude of the charge on each piece of tape if electrostatic force is great enough to support the weight of a 11.3 mg piece of tape a distance 1.00 cm above the other. for this problem, treat the each piece of tape as a point charge (this is only an approximation) [be sure to watch the video at the beginning of this chapter.]

Your starship, the aimless wanderer, lands on the mysterious planet mongo. as chief scientist-engineer, you make the following measurements: a 2.50-kg stone thrown upward from the ground at 14.0 m/s returns to the ground in 5.70 s ; the circumference of mongo at the equator is 2.20×10^5 km ; and there is no appreciable atmosphere on mongo. (a) the starship commander, captain confusion, asks for the following information: what is the mass of mongo? (b) if the aimless wanderer goes into a circular orbit 2.20×10^4 km above the surface of mongo, how many hours will it take the ship to complete one orbit? (c) an unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 44.0 km . to the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 23.0 m/s . if nothing is done to correct its orbit, with what speed (in km/h) will the spacecraft crash into the lunar surface?