A TV with a power rating of 267 W uses 1.9 kWh in one day. How many hours was the TV during that day?
1 answer:
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Answer:
The answer is β=0,85 rads
Explanation:
As the ladder is leaning against the building, we can imagine there´s a triangle where 20ft is the hypotenuse and 15ft is the maximum vertical distance between the ladder and the ground, it means, the leg opposite to β which is the angle we need
Let β(betha) be the angle between the ladder and the ground
We also know that
In this case we will need to find β, this way:
Then β=48,6°
We also have that 2πrads is equal to 360°, in this way we find how much β is in radians:
then we find β=0,85rads
To minimize neutron leakage from a reactor, the ratio of the surface area to the volume should be a minimum. For a given volume V the ratio of the sphere will be .
We know that the surface area and volume of the sphere is given by:
Therefore, the ratio between the surface area and the volume for the sphere will be:
Equating the volume to the constant c, we will find the value of .
Substituting the value of r in the ration between surface area and volume, we get:
Calculating the constants, we get:
Hence, the ration between surface area and volume is
To learn more about surface area and volume of sphere, refer to:
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