When a temperature of a pot in a kiln is 1 , 200 ∘ 1,200∘f, an artist turns off the heat and leaves the pot to cool at a controlled rate of 81 ∘ 81∘f per hour. express the temperature of the pot in degrees celsius as a function of the time t t (in hours) since the kiln was turned off?

We should split the problem into three parts.

1) Amount of heat necessary to bring the ice from [tex]T=-18^{\circ} C[/tex] to [tex]T=0^{\circ} C[/tex]. This is given by:
[tex]Q=m C_{ice} \Delta T[/tex]
where [tex]m=76 g=0.076 kg[/tex] is the mass, [tex]\Delta T=18 ^{\circ} C=18 K[/tex] is the variation of temperature, and [tex]C_{ice} = 2.06 kJ/(Kg K)[/tex] is the specific heat of ice. Calculating, we get
[tex]Q=(0.076 kg)(2.06 kJ/(kg K))(18 K)=2.82 kJ[/tex]

2) When the ice is at [tex]T=0^{\circ} C[/tex], the heat added at this point does not change the temperature of the ice, because it is used to fuse it into water. The amount of heat needed to cause the complete fusion of ice is
[tex]Q=m L[/tex]
where [tex]L=334 kJ/kg[/tex] is the latent heat of fusion of ice. So,
[tex]Q=(0.076 kg)(334 kJ/kg)=25.38 kJ[/tex]

3) Now the ice is transformed into water. We have to bring it to [tex]T=25^{\circ} C[/tex], so the variation of temperature is [tex]\Delta T=25-0=25 ^{\circ} C=25 K[/tex]. The amount of heat needed to bring the water at this temperature is
[tex]Q=m C_{water} \Delta T[/tex]
where [tex]C_{water} = 4.186 kJ/(kg K)[/tex] is the specific heat of water. Therefore,
[tex]Q=(0.076 kg)(4.186 kJ/(kg K))(25 K)=7.95 kJ[/tex]

4) So, the total heat needed for the entire process is:
[tex]Q_{tot}=2.82 kJ + 25.38 kJ+7.95 kJ=36.15 kJ[/tex]

Final answer:

The total heat energy required to convert 76.0 g of ice at -18.0°C to water at 25.0°C is 35.184 kJ. This includes the energy to heat the ice to 0°C, melt the ice, and heat the water to 25°C.

Explanation:

To calculate the heat energy required, we need to account for three processes: heating the ice to 0°C, melting the ice, and then heating the water to 25°C.

For the first process, we use the formula Q=mcΔT, where m is mass, c is specific heat, and ΔT is the temperature change. Ice has a specific heat of 2.09 J/g°C. So Q = 76.0 g * 2.09 J/g°C * 18°C = 2854.56 J.

For the second part, we use the formula Q = mLf, where m is mass and Lf is heat of fusion. For ice, Lf = 334 kJ/kg or 334 J/g. So Q = 76.0 g * 334 J/g = 25384 J.

For the last process, we once again use Q=mcΔT, this time with the specific heat of water, 4.184 J/g°C. So Q = 76.0 g * 4.184 J/g°C * 25°C = 7946 J.

To get the total heat energy required, we add these three quantities together and convert from joules to kilojoules. Q_total = (2854.56 J + 25384 J + 7946 J) / 1000 = 35.184 kJ. So, it requires 35.184 kJ of heat energy to convert 76.0 g of ice at -18.0°C to water at 25.0°C.

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The answer is the third option, "about 18,000 miles per hour". If you just want to get a spaceship into orbit around the Earth, the spaceship will need to reach a minimum speeds of about 4.9 miles per second, which is equivalent to 17,600 miles per hour (about 18,000 miles per hour to the nearest thousand).

This question deals with the concepts of the actual weight and apparent weight.

The apparent weight of the person is "827.9 N".

APPARENT WEIGHT

The apparent weight of an object is the reaction of the elevator floor on the person while the elevator is in accelerated motion. It is not the actual weight but the weight felt by the person for that time. In this case the elevator is moving up. Hence the apparent weight will be:

[tex]W_a=m(g+a)=mg+ma\\W_a=W+ma[/tex]

where,

W = actual weight = 639 Nm = mass = [tex]\frac{W}{g}=\frac{639\ N}{9.81\ m/s^2}[/tex] = 65.14 kga = acceleration = 2.9 m/s²[tex]W_a[/tex] = apparent weight = ?

Therefore,

[tex]W_a=639\ N + (65.14\ kg)(2.9\ m/s^s)[/tex]

[tex]W_a=827.9\ N[/tex]

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Final answer:

The scale reading in an elevator accelerating upwards will display an increased weight due to the additional force of acceleration. When an elevator accelerates with a magnitude of 2.90 m/s^2, the scale will show a higher value than the normal weight, calculated by the sum of gravitational force and force of acceleration.

Explanation:

When you step onto a scale in an elevator that is accelerating upwards with a magnitude of 2.90 m/s2, the scale reading will be higher than your normal weight due to the additional force required to accelerate you upwards. Given that your normal weight is 639 N, we can calculate the new scale reading by incorporating the effects of the elevator's acceleration using Newton's second law of motion.

To find the new scale reading, we first determine the apparent weight. The apparent weight is the sum of the true weight (gravitational force) and the force of acceleration (ma).

Apparent weight = True weight (W) + Force of acceleration (ma)

Where the true weight W = mg (mass times gravity), and a is the acceleration of the elevator.

Assuming Earth's gravity to be 9.81 m/s2, we can calculate the apparent weight as follows:

Apparent weight = mg + ma

Now, we need to find the mass (m) from the given weight (639 N), which is m = W/g = 639 N / 9.81 m/s2.

Then plug the mass and the given acceleration into the equation for apparent weight.

The scale reading in an accelerating elevator is directly proportional to the acceleration; it increases as the elevator accelerates upwards. However, once the elevator reaches a constant velocity, the scale reading will return to your normal weight, 639 N, because there will be no additional force from acceleration (a = 0).

The correct option is this: IT WOULD MOVE IN A CURVED CIRCULAR PATH.
Objects that are travelling in circular paths change directions all the time as they move round the circle, but they are prevented from moving off in a straight line by centripetal force. The centripetal force keeps pulling the objects towards the center of the circle. 

B. It would move in a line toward the circle’s center.

Explanation:

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