HELP ME PLEASE A motor is used to lift a 10 kg mass 2 m above the ground in 4 s. If the power input to the motor is 100 mathbb W what is the efficiency of the motor?
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The largest observatory complex in the world is on mauna kea, the tallest mountain on earth. what are some factors astronomers consider when selecting an observatory site? don’t forget practical ones. should astronomers, for example, consider building an observatory on denali (mount mckinley) or mount everest?

Which is gerrymandering a problem for the house of representatives but not the senate? a.) members of the house are greatly influenced by their political parties. b.) senators serve longer terms than members of the house. c.) members of the house are more influenced by changes in public opinion. d.) senators are elected in statewide elections rather than in specific districts.

When a charged balloon sticks to a wall, the downward gravitational force is balanced by an upward static friction force. the normal force is provided by the electrical attraction between the charged balloon and the equal but oppositely charged polarization induced in the wall's molecules. if the mass of a balloon is 1.2 g, its coefficient of static friction with the wall is 0.71, and the average distance between the opposite charges is 0.80 mm, what minimum amount of charge must be placed on the balloon in order for it to stick to the wall? express your answer to two significant figures and include appropriate units.