Every day teacher Rodriguez drinks a cup of coffee before her 9:00 am class. Suppose the temperature of the coffee is 224º F when she pours it into her cup at 8:30 am, 13 minutes later the coffee cools to 149º F in a room that is 53º F. However, teacher Rodriguez will never drink her coffee until it cools to just 86º F. How many minutes after it is served will she drink her coffee? Every day teacher Rodriguez drinks a cup of coffee before her 9:00 am class. Suppose the temperature of the coffee is 224º F when she pours it into her cup at 8:30 am, 13 minutes later the coffee cools to 149º F in a room that is 53º F. However, teacher Rodriguez will never drink her coffee until it cools to just 86º F. How many minutes after it is served will she drink her coffee?

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.

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speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.