Newton’s law of cooling


    1. A body in air at 25 C cools from 100 C to 75 C in 1 minute. Find the temperature of the body at the end of 3 minutes
    2. If the temperature of the air is 30 degree Celsius and a metal ball cools from 100 degree Celsius to 70 degree Celsius in 15 minutes, find how long will it take for the metal ball to reach a temperature of 40 degree Celsius
    3. A bottle of mineral water at a room temperature of 72 degree Fahrenheit is kept in a refrigerator where the temperature is 44 degree Fahrenheit. After half an hour, water cooled to 61 degree Fahrenheit.
    4. A body is originally at 80 degree Celsius cools down to 60 degree Celsius in 20 minutes. If the air temperature is 40 degree Celsius, what will be the temperature of the body after 40 minutes?
    5. A metal ball is heated to a temperature of 100 degree Celsius and it is placed in water which is at 40 degree Celsius. If in 4 minutes the temperature of the ball is reduced to 60 degree Celsius. Find the time at which the temperature of the ball is 50 degree Celsius


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