A.) A goose is flying south for the winter at a constant speed. Keep in mind tha

Question

A.) A goose is flying south for the winter at a constant speed. Keep in mind that one mile is 1.61 km , and one pound is 454 g .

The goose has a mass of 22.9 lb (pounds) and is flying at 11.9 miles/h (miles per hour). What is the kinetic energy of the goose in joules?

B.) An unknown mass of each of the following substances, initially at 25.0 C, absorbs 1930 J of heat. The final temperature is recorded as indicated. Find the mass of each substance.

a. Pyrex glass (Tf=55.2 C)

            b. Ethanol (Tf=44.3 C)

C. How much heat must be absorbed by a 25.0 g sample of water to raise its temperature from 30.0 C to 44.0 C? (For water, Cs=4.18J/gC.)

Explanation / Answer

A)

Ek = 1/2*m*V ^2

m = 22.9 lb = 22.9*0.454 = 10.3966 kg

v = 11.9 mi/h = 11.9*1.61*1000/3600 = 5.321 m/s

Ek = 1/2*10.3966 *5.321 ^2 = 147.179 J

B)

Q = m*Cp*(Tf-Ti)

for pyrex

1930 = m*0.75*(55.2-25)

m = 1930/(0.75*(55.2-25)) = 85.20 g of pyrex

for ethanol

1930 = m*2.46*(44.3-25)

m = 1930/(2.46*(44.3-25)) = 40.65 g

c)

Q = m*Cp*(Tf-Ti)

Q = 25*4.18*(44-30) = 1463 J

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