What is the work input to lift a box of 810 with a 50% mechanical efficiency?

Work input = 1620

Explanation:

Given the following data;

Work output = 810

Efficiency = 50%

To find the work input;

Mathematically, efficiency is given by the formula;

Substituting into the formula, we have;

Cross-multiplying, we have;

Work input = 1620

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.

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