1. a) The pendulum in a grandfather clock is made of brass and keeps perfect time at 25°C. How much time is gained or lost in a year if the clock is kept at 20°C? The coefficient of linear expansion of brass is 20.10^-6/C.

b) A brass ball does not fit through an aluminum ring at 20°C. The diameter of the ball is 5.001 cm and the inner diameter of the ring is 5.000 cm. At what temperature does the ball just fit through the ring? The coefficient of linear expansion of aluminum is 24.10^-6/C°.

2 Determine the latent heat of fusion of mercury using the following calorimeter data: 1.20 kg of solid Hg at its melting point of -39.0°C is placed in a 0.620-kg aluminum calorimeter with 0.500 kg of water at 15.0°C; the resulting equilibrium temperature is 7.06°C. The specific heat of mercury is 138 J/kg• C°. The specific heat of aluminum is 900.1/kg• C.

3 A calorimeter consists of a massless beaker that contains 20.0 g of solid water (i.e., ice) at -30 °C. Then 100.0 g of iron at 70.0 °C are added to the calorimeter. a) Find the final temperature of the calorimeter after equilibrium is reached. b) If the final temperature is 0 °C, what fraction of the ice is melted? c) During the process of reaching thermal equilibrium, how much heat is absorbed by the H₂0? by the iron? What is the sum of these two heats? Why must the sum have this value? [The specific heat of iron is 470 J/kg C.

4 The intensity of solar radiation reaching the earth on top of its atmosphere is about 1350 J/m²s. This value is called the solar constant. It varies from 1308 J/m²s to 1398 J/m²s depending on the earth-sun distance.

a) Assuming the Sun radiates like a blackbody, estimate the surface temperature of the sun.

b) Assuming the earth behaves like a blackbody, how much energy is absorbed per unit time. What is its equilibrium temperature if all this energy is re-radiated back into space?