A pulley system operates with 40% efficiency. if the work put in is 200 joules, how much useful work is produced?
2 answers:
Answer:
The useful work produced by a pulley system is 80 Joules.
Explanation:
Efficiency is a measure of how much work is preserved in a process. The formula for efficiency is the energy output, divided by the energy input, expressed as a percentage. A perfect process would have an efficiency of 100%.
η = efficiency (Greek letter "eta")
Wo = the work or energy produced by a process. Units are Joules (J).
Wi = the work or energy put in to a process. Units are Joules (J).
Wo = 0.4*200J
Wo = 80 J
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Explanation:
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Answer:
(a) 28690 m/s (b)
Explanation:
The orbital speed is define as:
(1)
Where r is the radius of the trajectory and T is the orbital period.
To determine the orbital speed of the Earth it is necessary to know the orbital period and the radius of the trajectory. That can be done by means of the Kepler's third law and average velocity equation.
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(2)
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(3)
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⇒
Replacing all those values in equation 3 it is gotten:
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It is necessary to pass from meters to astronomical unit (AU), 1 AU is defined as the distance between the Earth and the Sun.
That can be expressed in units of years.
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<u>So Earth orbital speed around the Sun is 28690 m/s.</u>
<em>b) What is its kinetic energy?</em>
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(4)
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(5)
M will be isolated in equation 5:
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<u>Hence, the kinetic energy of Earth is .</u>