Question 1- What is the minimum number of 1/2 cm expansion joints that must be put in a 100-m wall made of sheets of plasterboard in order to prevent buckling if the temperature can range from -5°C to 40°C? (Plasterboard has a coefficient of linear expansion, α = 5 x 10^-6 K^-1)

Question 2- A 12-kg mass on a spring undergoes SUM with a period of 16 s. Its amplitude is 5.0 cm. Draw a sketch of the situation, list knowns and unknowns, and then find the spring constant, k.

Question 3- Explain, using the atomic model of matter,

(a) Why hot air rises from the baseboard heating unit in a room.

(b) Why cold air sinks to the bottom of a refrigerator.

Question 4- A stretched string is 4.5 m long vibrates in a standing wave pattern with 6 loops. The vibrating string has a frequency string has a frequency f = 360 Hz. Draw a sketch of the situation then answer the questions.

Question 5- A piano note of unknown frequency, f, and a tuning fork with f= 384 Hz are both sounded at the same time. Beats are heard. The frequency of the beats, f_beat = 4 Hz. When the same piano key is played at the same time as a tuning fork with frequency 395 Hz, the beat frequency is 7 Hz. What is the frequency of the piano note?

Question 6- Two pots are identical except that the flat bottom of one is aluminum, whereas that of the other is steel. Water in these pots is boiling away at 100.0°C at the same rate. The temperature of the heating element on which the aluminum bottom is sitting is 180.0°C. Assume that heat enters the water only through the bottoms of the pots and find the temperature of the heating element on which the copper bottom rests. (k for aluminum = 240 J/(s • m • C°), k for steel =14J/(s • m • C^o)).