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amm1812
2 years ago
7

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 W. what is the efficien

cy of the motor?
(Show Work)
Physics
1 answer:
Bad White [126]2 years ago
7 0

Answer:

98%

Explanation:

Given parameters

Mass of motor = 10kg

Height = 2m

Time = 2s

Power input = 100w

Unknown

Efficiency = ?

Solution

Efficiency is the percentage of the power output to the power input.

Power is the rate at which work is done.

Power output = mass x g x height / time

g is the acceleration due to gravity

Power output = 10x 2 x 9.8 / 2 = 98W

Efficiency = power output/ power input x 100

Efficiency = 98/100 x 100 = 98%

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Minchanka [31]

Answer:

The image distance from right lens is 2.86 cm and image is real.

Explanation:

Given that,

Focal length of left lens = 10 cm

Focal length of right lens = 5 cm

Distance between the lenses d= 15 cm

Object distance = 50 cm

We need to calculate the image distance from left lens

Using formula of lens

\dfrac{1}{v}=\dfrac{1}{f}-\dfrac{1}{u}

Put the value into the formula

\dfrac{1}{v}=\dfrac{1}{10}-\dfrac{1}{-50}

\dfrac{1}{v}=\dfrac{3}{25}

v=8.33\ cm

We need to calculate the image distance from right lens

The object distance will be

u = 15-8.33 = 6.67\ cm

Using formula of lens

\dfrac{1}{v}=\dfrac{1}{f}-\dfrac{1}{u}

Put the value into the formula

\dfrac{1}{v}=\dfrac{1}{5}-\dfrac{1}{-6.67}

\dfrac{1}{v}=\dfrac{1167}{3335}

v=2.86\ cm

The image is real.

Hence, The image distance from right lens is 2.86 cm and image is real.

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Harrizon [31]

Answer:

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