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andreev551 [17]
2 years ago
9

A 2-kW resistance heater in a water heater runs for 3 hours to raise the water temperature to the desired level. Determine the a

mount of electric energy used in both kWh and kJ.
Physics
1 answer:
nexus9112 [7]2 years ago
7 0

Power(p) = 2kW

Time(t)= 3 h

Work done(w) = ?

p = w / t

w = p × t

w = 2kW × 3 h

w = 6kWh

Converting 6kWh to Joules,

6kWh

6×(10^3)h ( k = 10^3 )

6×10^3×(60×60) ( 1 hour = 60 × 60 sec)

2.2×10^7 J in 2 significant figures

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Which is one way scientists indicate how precise and accurate there experimental measurements are
kherson [118]
They do the method 3 times to be sure. Because if you do it once, that could mean anything. If you do it twice, it may or may not have the same result. If you do it 3 times and it matches one of the previous answers, then it's likely that it's correct.
8 0
3 years ago
Which of the following are inertial reference frames? A. A car driving at steady speed on a straight and level road. B. A car dr
Aloiza [94]

Answers:

A. A car driving at steady speed on a straight and level road.

B. A car driving at steady speed up a 10∘ incline.

Explanation:

An object is said to be in an inertial reference frame if the net force acting on the object is zero. According to Newton's second law, this also means that the acceleration of the object is also zero:

F=ma

Since F=0, a=0 as well.

Let's now analyze each case.

A. A car driving at steady speed on a straight and level road. --> YES: this is an inertial reference frame, because the car is keeping a constant speed and a constant direction, so its velocity is not changing, and its acceleration is zero.

B. A car driving at steady speed up a 10∘ incline. --> YES: this is an inertial reference frame, because the car is keeping a constant speed and a constant direction, so its velocity is not changing, and its acceleration is zero.

C. A car speeding up after leaving a stop sign. --> NO: this is not an intertial reference frame, because the car is speeding up, so it is accelerating.

D. A car driving at steady speed around a curve. --> NO: this is not an inertial reference frame, because the car is changing direction, therefore its velocity is changing and so the car is accelerating.

So the only two choices which are correct are A and B.

8 0
2 years ago
Read 2 more answers
How many milligrams are equivalent to 150 dekagrams?
dybincka [34]
 i believe  the answer is 1.5e+6

hope this helps!

4 0
3 years ago
Read 2 more answers
Eric has a mass of 19.0 kg on the earth. What is Eric's weight on earth? What is Eric's weight on Mars? where the acceleration o
Tom [10]

Answer:

Weight on Earth = We = 186.2 N

Weight on Mars = Wm = 70.94 N

Explanation:

The weight of an object is defined as the force applied on the object by the gravitational field. The magnitude of weight is given by the following formula:

W = mg

were,

W= Weight of Eric

m = mass of Eric

g = acceleration due to gravity

ON EARTH:

W = We = Eric's Weight on Earth = ?

m = Eric's Mass on Earth = 19 kg

ge = acceleration due to gravity on Earth = 9.8 m/s²

Therefore,

We = (19 kg)(9.8 m/s²)

<u>We = 186.2 N</u>

<u></u>

ON MARS:

W = Wm = Eric's Weight on Mars = ?

m = Eric's Mass on Mars = 19 kg

gm = acceleration due to gravity on Mars = 0.381(ge) = (0.381)9.8 m/s² = 3.733 m/s²

Therefore,

Wm = (19 kg)(3.733 m/s²)

<u>Wm = 70.94 N</u>

3 0
3 years ago
As frequency increases, what happens to the tone (or pitch) of a sound? Which option is it?
icang [17]

Answer:

gets higher

Explanation:

There are videos that show the range of human hearing.  If you would play the video, you would notice that if the frequency increases, the pitch would also increase.

3 0
3 years ago
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