1. A piece of aluminum with a mass of 250 g is immersed in a trough of water filled to the brim. The mass of the overflown water is measured and found to be 93.0 g. What is the density of the piece of aluminum? (Apply Archimedes's principle and buoyancy) 2. A spherical balloon with a 10.0-m diameter is filled with helium gas. If the mass of the balloon material (including the helium in it) is 250 kg, what is the maximum load that it can just lift and float in the air. (Density of air is 1.225 kg/m', apply like question 1 above, but in air) 3. A parachuter has a total mass of 80 kg, with an effective surface area of 27 m . What is the terminal velocity if the air density is 1.18 kg/m' and the drag coefficient is 1.75? (Apply: mg = 1/2 CApv,?) 4. A certain ultraviolet radiation (an electromagnetic wave) has a frequency of 2.5x101 Hz. What is its wavelength in nanometer? (Apply c = af ) 5 . How much heat you need to transfer to 100 g of water at 60 'C to change it completely to water vapor at 100 C? (Apply Q = mcAT + mLi , get necessary parameters/coefficients from the slides of chapter#7) 6. 2.00 .C 106 .C A lead rod is connected between metal plates held at 2.00 "C and Lead 106 C. The rod has a length of 525 mm and a square cross section, 1.5 cm on a side. How much heat flows through the rod in one minute? 525 mm (Apply 28 = KA 1-12 , 1, get necessary coefficient from the chapter slides) 7 . The total surface area of a person's body is 1.8 m and her/his skin's temperature is 30 C. If she/he also absorbs radiation from the surroundings, which is at a temperature of 20 C, what is her/his net heat loss by radiation in one minute)? (Apply = EGA(T* - Ts#), take the emissivity of the body as unity, irrespective of skin pigmentation, get o from the chapter's slides). 8. During a strong storm the wind was blowing at a speed of 120 mi/h. Outdoor If some home has an average roof area of 200 m , what is the force P1 V1 exerted on the roof, and where its directed upward or downward? Indoor P2, V2 (Apply Bernoulli's equation at two sections of the air flow, outdoor and indoor, neglect the thickness of the roof, take 1 mi = 1609 m). Hint: Find P2 - P1 then F = (P2 - P1)A