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
1 answer:
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No net force and the photo shows
Answer:
Ec = 6220.56 kcal
Explanation:
In order to calculate the amount of Calories needed by the climber, you first have to calculate the work done by the climber against the gravitational force.
You use the following formula:
(1)
Wc: work done by the climber
g: gravitational constant = 9.8 m/s^2
M: mass of the climber = 78.4 kg
h: height reached by the climber = 5.42km = 5420 m
You replace in the equation (1):
(2)
Next, you use the fact that only 16.0% of the chemical energy is convert to mechanical energy. The energy calculated in the equation (2) is equivalent to the mechanical energy of the climber. Then, you have the following relation for the Calories needed:
Ec: Calories
You solve for Ec and convert the result to Cal:
The amount of Calories needed by the climber was 6220.56 kcal
Answer:
Volume of the sample: approximately .
Average density of the sample: approximately .
Assumption:
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- Volume of the cord is negligible.
Explanation:
<h3>Total volume of the sample</h3>The size of the buoyant force is equal to .
That's also equal to the weight (weight, ) of water that the object displaces. To find the mass of water displaced from its weight, divide weight with
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Assume that the density of water is . To the volume of water displaced from its mass, divide mass with density
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Assume that the volume of the cord is negligible. Since the sample is fully-immersed in water, its volume should be the same as the volume of water it displaces.
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Average density is equal to mass over volume.
To find the mass of the sample from its weight, divide with .
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The volume of the sample is found in the previous part.
Divide mass with volume to find the average density.
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