A hard rubber comb is pulled through a student's hair, and acquires a negative electric charge. This must mean that ---. Question 2 options:

the comb is electrically connected to the ground

the comb is taking electrons from the hair

the hair is taking protons from the comb

the comb is creating electrons

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

Steam enters an adiabatic diffuser at 150 kpa and 1208c with a velocity of 550 m/s. determine the minimum velocity that the steam can have at the outlet when the outlet pressure is 300 kpa.

Which planet do you think would be easiest for humans to colonize some day?