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2 years ago

How much money does a mixer use if the efficiency is 50% and it wastes 20J of energy ?

Physics

1 answer:

GalinKa [24]2 years ago

5 0

Answer:

Ei = 40J

Explanation:

Given the following data;

Efficiency = 50%

Energy output, Eo = 20 J

To find the amount of energy used by the mixer:

Efficiency = Eo/Ei * 100

Where;

Eo is the output energy.

Ei is the input energy.

Substituting into the formula, we have;

50 = 20/Ei * 100

Cross-multiplying, we have;

50Ei = 2000

Ei = 2000/50

Ei = 40J

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Steam at 100°C is condensed into a 38.0 g aluminum calorimeter cup containing 280 g of water at 25.0°C. Determine the amount of

KonstantinChe [14]

Answer:

7.2g

Explanation:

From the expression of latent heat of steam, we have

Heat supplied by steam = Heat gain water + Heat gain by calorimeter

mathematically,

$m_{s}c_{w} \alpha _{w}$ + $m_{s}l$ = $m_{w}c_{w} \alpha _{w}$ + $m_{c}c_{c} \alpha c_{c}$

L=specific latent heat of water(steam)=2268J/g

$c_{w}$ =specific heat capacity=4.2J/gK

$c_{c}$ =specific heat capacity of calorimeter =0.9J/gk

$m_{w}$ =280g

$m_{c}$ =38g

α=change in temperature

$\alpha _{c}$ =(40-25)=15

$\alpha _{w}$ =(40-25)=15

$\alpha _{s}$ =(100-40)=60

Note: the temperature of the calorimeter is the temperature of it content.

From the equation, we can make $m_{s}$ the subject of formula

$m_{s}=\frac{m_{w}c_{w} \alpha +m_{c}c_{c}\alpha}{c_{w}\alpha +l}$

Hence

$m_{s}=\frac{(280*4.2*15) +(38*0.9*15)}{(4.2*60) +2268} \\m_{s}=\frac{18153}{2520}\\ m_{s}=7.2g$

Hence the amount of steam needed is 7.2g

6 0

2 years ago

When a cold air mass and a warm air mass meet but are at a standstill, the boundary is called.

Sphinxa [80]

Answer:

Ur answer is Stationary Front

Explanation:

Stationary Front is when a cold air mass and a warm air mass but are at a standstill the boundary is called Stationary Front.

3 0

1 year ago

Which is a consequence of the third law of thermodynamics Energy is not always conserved. Engines cannot discharge waste heat. H

miss Akunina [59]

Heat engines are less than 100% efficient because absolute zero cannot be reached

8 0

3 years ago

Read 2 more answers

In a galvanic cell, electrons flow from the ________ to the _______ .

s2008m [1.1K]

Answer:

Explanation:

In a galvanic cell, electrons flow from the anothe to the cathode.

I hope you got the answer

7 0

2 years ago

A pipe that is open at both ends has a fundamental frequency of 320 Hz when the speed of sound in air is 331 m/s.

fenix001 [56]

Question

What is the length of the pipe?

Answer:

(a) 0.52m

(b) f2=640 Hz and f3=960 Hz

Explanation:

For an open pipe, the velocity is given by

$v=\frac {2Lf}{n}$

Making L the subject then

$L=\frac {nV}{2f}$

Where f is the frequency, L is the length, n is harmonic number, v is velocity

Substituting 1 for n, 320 Hz for f and 331 m/s for v then

$L=\frac {1*331}{2*320}=0.5171875\approx 0.52m$

(b)

The next two harmonics is given by

f2=2fi

f3=3fi

f2=3*320=640 Hz

f3=3*320=960 Hz

Alternatively, $f2=2\times \frac {v}{2L}$ and $f3=3\times \frac {v}{2L}$

$f2=2\times \frac {331}{2*0.52}=636.5 Hz\\f3=3\times \frac {331}{2*0.52}=954.8 Hz$

(c)

When v=367 m/s then

$f1= \frac {v}{2L}\\f1= \frac {367}{2*0.52}=352.9 Hz$

5 0

2 years ago