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nikdorinn [45]
3 years ago
13

When we say the sun is rising and the sun is setting, who is the observer? where should the observer be to see that the sun does

not move around the earth every 24 hours?
Physics
1 answer:
Kisachek [45]3 years ago
8 0
When we talk about that the sun rises and sets, an individual on the surface of the earth who is motionless or stationary is the spectator or observer. The observer may perhaps be on the moon to see that the sun does not travel all over Earth every 24 hours.
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Joy is a patient at a hospice center. She has sleep medication that is prescribed to be taken as needed. Joy does not feel sleep
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The right to make treatment choices



7 0
3 years ago
A. How many calories are needed to raise the temperature of 1 gram of water by 1 °C?
sweet-ann [11.9K]

A) 1 cal

B) 80 cal

C) 540 cal

Explanation:

A)

The amount of heat energy needed to raise the temperature of a certain mass of a substance is given by

Q=mC\Delta T

where

m is the mass of the substance

C is the specific heat capacity

\Delta T is the change in temperature

In this problem:

m = 1 g is the mass of water

C=1 cal/g^{\circ}C is  the specific heat capacity of water

\Delta T=1^{\circ}C is the change in temperature

So, the heat needed is

Q=(1)(1)(1)=1 cal

B)

For a solid substance at its melting point, the amount of heat needed to melt completely the substance is given by

Q=m\lambda_f

where

m is the mass of the substance

\lambda_f is the specific latent heat of fusion of the substance

In this problem:

- The ice is already at melting point, 0 °C

- Mass of the ice: m=1g

- Specific latent heat of fusion of ice: \lambda_f=80 cal/g

So, the heat needed is

Q=(1)(80)=80 cal

C)

For a liquid substance at its boiling point, the amount of heat needed to boil completely the substance is given by

Q=m\lambda_v

where

m is the mass of the substance

\lambda_v is the specific latent heat of vaporization of the substance

In this problem:

- The water is already at boiling point, 100 °C

- Mass of the water: m=1g

- Specific latent heat of vaporization of water: \lambda_v=540 cal/g

So, the heat needed is

Q=(1)(540)=540 cal

5 0
3 years ago
A car move at an initial velocity of 240m and reach at the final velocity of 540m in 8hours. calculate its acceleration.​
disa [49]

Answer:

a = 0.01m/s²

Explanation:

V_f = V_0+a*t

V_f = Velocity final

V_0 = Velocity initial

a = acceleration

t = time

a = (V_f-V_0)/t

a = (540m/s-240m/s)/((8hr)*(60min/1hr)*(60s/1min))

a = 0.01m/s²

6 0
2 years ago
In an electric furnace used for refining steel, the temperature is monitored by measuring the radiant power emitted through a sm
stiks02 [169]

Answer: 3.7×10¹²watts

Explanation:

Radiation is one of the mode of heat transfer and modes differs from each other based on their medium of heat transfer. Radiation is a process of transferring heat energy from one point to another without heating the intervening medium (no material medium is required).

According to Stefan's law of radiation, the rate of emission of radiant energy is directly proportional to the fourth power of its absolute temperature.

Mathematically, R = eAT⁴

e is constant of proportionality called emissivity. Emissivity varies depending on the type of body being considered.

For the question, we are considering black body and emissivity of black body is 1 being a perfect body.

A is the area of the body

T is the absolute temperature

e = 1

A = 0.5cm²

T = 1650°C

Rate of radiation = 1×0.5×1650⁴

= 3.7×10¹²watts.

The hole will therefore radiate 3.7×10¹²watts

3 0
3 years ago
Transverse waves travel with a speed of 20.0 m/s on a string under a tension of 6.00 N. What tension is required for a wave spee
marta [7]

Based on the sped of the waves and the tension as well as the needed wave speed, the required tension is 13.5 N.

<h3>What is the required tension?</h3>

Given the initial tension and speed, the tension that is required can be found by the formula:

= Initial tension x (Required speed / Initial speed)²

Solving gives:

= 6 x (30 / 20)²

= 6 x 9/4

= 13.5 N

In conclusion, the tension required is 13.5N.

Find out more on the tension on a wire at brainly.com/question/14290894.

#SPJ4

3 0
1 year ago
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