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Umnica [9.8K]
2 years ago
10

Two movers use a rope system to lift a box to a third-story apartment. They do 1,200 J of work on the rope system, and the rope

system does 1,020 J of work on the box. What is the efficiency
Physics
2 answers:
xeze [42]2 years ago
8 0
Efficiency is defined as the measure of the amount of work or energy is conserved in a certain process. At all times, in every process, work or energy is always lost or wasted due to certain interference. Not all work given is converted to useful work or energy. Thus , efficiency is calculated by dividing the energy or work output to the energy or work input then the value is multiplied by 100 to express efficiency as percentage.

Efficiency = work output / work input
Efficiency = (1020 J / 1200 J) = 85%
Kruka [31]2 years ago
3 0

Answer:

85%

Explanation:

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The food calorie, equal to 4186J , is a measure of how much energy is released when food is metabolized by the body. A certain b
vovangra [49]
<h2>The hiker will go up to 850 m on the hill</h2>

Explanation:

The total energy gained  by the hiker = 140 x 4186 J

This energy is consumed in the potential energy acquired , while climbing up the hill.

The potential energy P.E = mass of hiker x acceleration due to gravity x height

Thus

140 x 4186 = 69 x 10 x h

or h = \frac{4186x140}{69x10}  = 850 m

If the 20% of the total energy is used

the height h₀ = \frac{0.2x4186x140}{69x10} = 170 m

5 0
2 years ago
A certain part of a flat screen TV has a thickness of 150 nanometers. How<br> many meters is this?
Bess [88]

Answer:

1.5e-7 meters

.00000015 meters

Explanation:

.000000001 meters = 1 nanometer. Multiply that by 150 and an answer is there.

5 0
2 years ago
The total negative charge on the electrons in 1kg of helium (atomic number 2, molar mass 4) is____________.
tekilochka [14]

Answer:

Explanation:

n = \frac{m}{M}

n = \frac{1000}{4}

         = 250 moles.

    N  = n×6.02×10^{23}

        = 1.505×10^{26}

Total charge = (1.505×10^{26}) × (1.6×10^{-19})

                     = 2.4×10^{7} C.

4 0
2 years ago
Read 2 more answers
1. A 3.0 kg mass is tied to a rope and swung in a horizontal circle. If the velocity of the mass is 4.0 ms and
saul85 [17]

10.67m/s²

32N

Explanation:

Given parameters:

Mass of the body = 3kg

velocity of the mass = 4m/s

radius of circle = 0.75m

Unknown:

centripetal acceleration = ?

centripetal force = ?

Solution:

The centripetal force is the force that keeps a radial body in its circular motion. It is directed inward:

   Centripetal acceleration  = \frac{v^{2} }{r}

   v is the velocity of the body

    r is the radius of the circle

  putting in the parameters:

   Centripetal acceleration = \frac{4^{2} }{0.75}

    Centripetal acceleration = 10.67m/s²

Centripetal force = m  \frac{v^{2} }{r}

          m is the mass

 Centripetal force = mass x centripetal acceleration

                              = 3 x 10.67

                              = 32N

learn more:

Acceleration brainly.com/question/3820012

#learnwithBrainly

4 0
2 years ago
The amount of steering wheel movement needed to turn will ____________ the faster you go.
Naddika [18.5K]

Answer:

The answer to your question is Decrease

4 0
1 year ago
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