Answer:
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Explanation:
Answer:
71195 seconds or 19.8 hours
Explanation:
Because the steel will be melted, beginning from room temperature, energy is needed to heat it from room temperature to 1600°C and another to melt it at 1600°C.
We take room temperature to be 27°C, the specific heat capacity of steel to be 420 J/kg/K and the specific latent heat of fusion of steel to be 440 J/kg.
The heat required to heat the steel from room temperature to 1600°C is given by

is the mass,
is the specific heat capacity and
is the change in temperature.

The heat required to melt it at 1600°C is

is the mass and
is the specific latent heat of fusion of steel.

Adding both, the heat required is 
Because the oven is 65% efficient, its output power = 
Now, energy = power * time
Time = Energy/power

Answer:
56 J
Explanation:
The following data were obtained from the question:
Energy 1 (E₁) = 7 J
Extention 1 (e₁) = 1.8 cm
Extention 2 (e₂) = 1.8 + 3.6 = 5.4 cm
Energy 2 (E₂) =?
Energy stored in a spring is given by the following equation:
E = ke²
Where E is the energy.
K is the spring constant.
e is the extension.
E = ke²
Divide both side by e²
K = E/e²
Thus,
E₁/e₁² = E₂/e₂²
7/ 1.8² = E₂/ 5.4²
7 / 3.24 = E₂/ 29.16
Cross multiply
3.24 × E₂ = 7 × 29.16
3.24 × E₂ = 204.12
Divide both side by 3.24
E₂ = 204.12 / 3.24
E₂ = 63 J
Thus, the additional energy required can be obtained as follow:
Energy 1 (E₁) = 7 J
Energy 2 (E₂) = 63 J
Additional energy = 63 – 7
Additional energy = 56 J
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Answer:
Power = 251.9 Watts
Explanation:
Power = Work Done / Time taken
Power = 3441 / 13.66
Power = 251.9 Joule / Second
Power = 251.9 Watts