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andreev551 [17]
3 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]3 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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Why is it incorrect to say that astronauts are weightlesS in space while orbiting Earth in a space shuttle?​
Mamont248 [21]

This is because Gravity exists everywhere in the universe.

<h3>What is Gravity?</h3>

This is the force of attraction which acts on all matters in the universe. Astronauts appear weightless while in orbiting the Earth because the space shuttle and the astronauts are in free fall around it.

They fall at the same rate as the space shuttle which is why the astronauts appear weightless.

Read more about Gravity here brainly.com/question/88039

6 0
2 years ago
If you weigh 690 N on the earth, what would be your weight on the surface of a neutron star that has the same mass as our sun an
lana [24]

Answer:

Explanation:

Given that,

Mass of star M(star) = 1.99×10^30kg

Gravitational constant G

G = 6.67×10^−11 N⋅m²/kg²

Diameter d = 25km

d = 25,000m

R = d/2 = 25,000/2

R = 12,500m

Weight w = 690N

Then, the person mass which is constant can be determined using

W =mg

m = W/g

m = 690/9.81

m = 70.34kg

The acceleration due to gravity on the surface of the neutron star is can be determined using

g(star) = GM(star)/R²

g(star) = 6.67×10^-11 × 1.99×10^30 / 12500²

g (star) = 8.49 × 10¹¹ m/s²

Then, the person weight on neutron star is

W = mg

Mass is constant, m = 70.34kg

W = 70.34 × 8.49 × 10¹¹

W = 5.98 × 10¹³ N

The weight of the person on neutron star is 5.98 × 10¹³ N

5 0
3 years ago
How to convert 250 newton to pounds? It is likely to be difficult to move?
maxonik [38]
I have no idea I need the answer too
3 0
3 years ago
Two identical stones are thrown from the top of a tall building. Stone 1 is thrown vertically downward with an initial speed v,
Molodets [167]

If the resistance of the Air is ignored, we can use the theory given by Galileo in which he warned that the thermal velocity of a body in free fall was given by

v= \frac{1}{2}gt

Where

g = Gravitational acceleration

t = time

As we can see the speed of objects in free fall is indifferent to the position that is launched (as long as the resistance of the air is ignored) or its mass.

Both bodies will end with the same thermal speed.

5 0
3 years ago
A gas, behaving ideally, has a pressure P1 and at a volume V1. The pressure of the gas is changed to P2. Using Avogadro’s, Charl
Bond [772]

Answer:

Boyle's Law

\therefore P_1.V_1=P_2.V_2

Explanation:

Given that:

<u><em>initially:</em></u>

pressure of gas, = P_1

volume of gas, = V_1

<em><u>finally:</u></em>

pressure of gas, = P_2

volume of gas, = V_2

<u>To solve for final volume</u> V_2

<em>According to Avogadro’s law the volume of an ideal gas is directly proportional to the no. of moles of the gas under a constant temperature and pressure.</em>

<em>According to the Charles' law, at constant pressure the volume of a given mass of an ideal gas is directly proportional to its temperature.</em>

But here we have a change in the pressure of the Gas so we cannot apply Avogadro’s law and Charles' law.

Here nothing is said about the temperature, so we consider the Boyle's Law which states that <em>at constant temperature the volume of a given mass of an ideal gas is inversely proportional to its pressure.</em>

Mathematically:

P_1\propto \frac{1}{V_1}

\Rightarrow P_1.V_1=k\ \rm(constant)

\therefore P_1.V_1=P_2.V_2

5 0
3 years ago
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