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yuradex [85]
3 years ago
7

The resistance of an electric heater is 50 Ω when connected to 120 V. How much energy does it use during 15 min of operation?

Physics
1 answer:
STALIN [3.7K]3 years ago
7 0

Answer:

Explanation:

I = V/R = 120 V/ 50 Ω = 2.4 A

P = VI = 120(2.4) = 288 W = 288 J/s

288 J/s (15 min(60s / min)) = 259,200 J

or the electric company would charge for

288 W / (1000 W/kW)•(15/60) hr = 0.072 kW•hr

At $0.20 / kW•hr, that would be under 1½ cents

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7 0
3 years ago
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hi :) is it true that zero acceleration means the object can be moving at constant velocity or at rest?
nirvana33 [79]

Answer:

No

Explanation:

Please let me know if my answer is correct

7 0
3 years ago
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Please any one help me
Hatshy [7]

Answer:

Which one are we supposed to do

Explanation:

4 0
2 years ago
Please help.
cestrela7 [59]
Hello,

<span>A police car parked on the side of the highway emits a 1200 Hz sound that bounces off a vehicle farther down the highway and returns with a frequency of 1250 Hz. 

How fast is the vehicle going?

Doppler equation formula: </span>ƒL = ƒS(v - vL)/(v - vS)

The wave returns with a frequency of 1250 Hz, the <span>echo frequency is higher; the car must be traveling towards the police car. 

</span><span>The wave echo is coming back towards the police car at the same speed as the sound wave travels towards the moving car so t</span><span>he relative speed between the cars is half of the speed of the echo.

* </span><span>speed of sound equals about 337 m/s </span>

2v / 337 = (1250/1200) - 1 
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<span>v = 7.02 m/s
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Thus, the vehicle is going 7.02 m/s.

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3 0
3 years ago
An open-end mercury manometer is connected to a low-pressure pipeline that supplies a gas to a laboratory. Because paint was spi
almond37 [142]

Answer:

A. Using

Pgauge= Pmanometer

And we know that

Pgauge= deta(hpg)

So deta h = Pgauge/density x g

So

= 7.5(6894.76/1psig)/ 13.6*10^3*9.8m/s²)

= 387.9mm

So to find height of pipe connected to the pipe we say

= h -deta h

= 900-387.97mm

=512.02mm

B. We use manometry principle

Pgas+density xg(25*10^3)-PX density{h-(H-0.25)=0

So

Finally Pgas= 6.54psig

3 0
3 years ago
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