Question

A student is making a cup of coffee and is adding milk to the coffee to cool it down to a drinkable temperature of 50 °C. There is 142 ml of coffee at 85 °C in her cup. You may assume that the specific heat capacity of coffee is the same as that for water; and that the densities of water, coffee and milk are the same. Given: 1 litre = 0,001 cubic meter.

A. Determine how much milk at 4 °C she should add to the coffee.

B. When will the rate of heat loss be the greatest?

C. Which principle did you use to come to your conclusion above?

Answer 1

rate og when = ST = given then dencity of water, milk and Coffice are equal and specfic heat Capacity of milk = 3.975 gic and spectic heat capacity of Coffice is = 4.259. heat How Caffles start decreasing tempreture con m. Ccoffice ( 4-25 JJ (85-50) mill start increasing tembretere (2) = m... (3.97) (2) = m milk ( 3.97) (50-4) (O2) = Mmick (3.97) (46) (o, 02) m Coffee And milk oT when both mix then mcoffice (4.25 I St J (35) = Mmilk (3.91) (06) Mmius Mcoffee 4.25 3.97 35 46 V milk x S = Voffice X8 (114.30) V milk 142 X 4.25 3.97 X 35 46 [ milk 114. 30 ml

B -- to do the rate of heat, hass is maximum at intial because rate of heat logo is directily perposnal Change in tempretute. a (OT) dt Heat tranferred from one objects to other object or via versa It work on principal on radiation, conduction and connection.