Name : e-mail: Applied Physics II Exam One Winter 2006-2007 Multiple Choice ( 7 Points ): 1. Pure nitrogen gas is contained in a sealed tank containing a movable piston. The initial volume, pressure and temperature are 0.020 m 3, 200 kpa, and 300K. If the volume is decreased to 0.010 m 3 and the pressure increased to to 400 kpa, what is the final temperature? a. 300 K b. 600 K c. 150 K d. 100 K 2. Convert 65 O F to degrees Celsius and to Kelvin. a. 18.33 O C and -254.82 K b. 18.33 O C and 291.48 K c. 149.0 O C and -124.15 K d. 149.0 O C and 422.15 K 3. A sidewalk is comprised of slabs of concrete ( a = 12 X 10-6 O C 1 ) that are 1.0 meter square when the temperature is 32.0 O F. How much of a space should be placed between each slab so that there is no buckling when the temperature reaches 100 O F? a. 1.632 mm b. 2.67 cm c. 0.45 mm d. 0.816 mm 4. A plastic sphere floats in water ( r = 1000 kg/m 3 ) with 50 % of its volume submerged. This same sphere floats in glycerin with 40 % of its volume submerged. What is the density of the sphere and of the glycerin? a. 1000 kg/m 3 and 500 kg/m 3. b. 1250 kg/m 3 and 1000 kg/m 3. c. 500 kg/m 3 and 1250 kg/m 3. d. 600 kg/m 3 and 1300 kg/m 3.
5. A solid brass sphere is initially surrounded by air and the air pressure is 1.0 X 10 5 N/m 2. It has a volume of of 0.50 m 3. It is lowered into the ocean to a depth where the pressure is 2.0 X 10 7 N/m 2. By how much does the volume change? ( The bulk modulus of brass is b = 6.1 X 10 10 N/m 2. ) a. -1.6 X 10-4 m 3. b. +1.6 X 10-4 m 3. c. -2.12 X 10-4 m 3. d. +2.12 X 10-4 m 3. 6. What is pre-stressed concrete? a. Concrete that has been heated to a very high temperature. b. Concrete that has been mixed with an extra measure of lime. c. Concrete that has been reinforced with steel rods under tension to prevent sagging. d. Concrete that has been mixed with fragments of steel to strengthen it. 7. A 200 kg load is hung on a wire having a length of 4.0 meters. The cross-sectional area is 0.20 X 10-4 square meters. The Young's Modulus is 8.0 X 10 10 N/m 2. How much does the length increase, i.e. How much does the wire stretch? a. 4.90 mm b. 8.90 mm c. 2.22 mm d. 6.76 mm 8. An ideal gas occupies a volume of 100 cubic centimeters at 20 O C and 100 kpa. Find the number of moles of gas in the containers. a. 1.60 X 10-4 moles b. 4.11 X 10-6 moles c. 2.00 X 10-4 moles d. 8.12 X 10-4 moles
9. When the temperature of water at atmospheric pressure decreases to 0.0 O C, ice can be formed. The ice floats on the top water because: a. the density of water at 100 O C increases due to thermal expansion, a phenomenon peculiar to water. b. the density of water at 0 O C decreases due to thermal expansion, a phenomenon peculiar to water. c. the density of water at 4 O C decreases, a phenomenon peculiar to water. d. the density of water at 4 O C increases due to thermal expansion, a phenomenon peculiar to water. 10. The term viscosity of a fluid is used to describe: a. the degree of internal friction in the fluid, i.e., the resistance between adjacent layers. b. the density of the fluid. c. the degree of friction between the fluid and the walls of the container or pipe it is in. d. the density of the fluid compared to the density of fresh water.
Problem One ( 18 Points ): In a car lift used in service station, compressed air exerts a force on a small piston that has a radius of 5.00 cm. This pressure is transmitted by a non-compressible fluid to a piston that has a radius of 15.0 cm. The 15.0 cm piston is used to lift a car with a mass of 1360 kg. F 1 1360 kg R 1 = 5 cm R 2 = 15 cm F 2 a. What must be the magnitude of the minimum force exerted on larger piston? b. What must be the magnitude of the minimum force exerted on the smaller piston? c. What must be the air pressure used to exert the force needed on the smaller piston? d. What is the pressure exerted on the larger piston? e. If the car is lifted 2.0 meters, how much work was done by the force F 2? f. If the car is lifted 2.0 meters, how much work was done by the force F 1? Extra Credit ( 3 points): How far did the smaller piston move if the car was raised 2.0 meters?
Problem Two ( 12 Points ): A water hose 2.5 cm in diameter is used by a gardener to fill a 30.0 Liter bucket. The gardener notes that it takes 1.00 minute to fill the bucket. A nozzle is then attached that has a cross sectional area of 0.50 cm 2. The nozzle is held so that the water is projected horizontally from a point 1.0 meters above the ground. Hose nozzle 1.0 m x=? a. What is the volume flow rate through the hose? b. What is the velocity of the water into the nozzle? c. What is the velocity of the water out of the nozzle? d. Over what horizontal distance can the water be projected?
Extra Credit ( 5 Points ): h Total length of string is 2.00 meters. A helium-filled balloon is tied to a 2.00 meter long string with a uniform mass of string of 0.05 kg. Assume the balloon is spherical with a radius of 0.4 meters. When the balloon is released, it raises to a height h and then remains in equilibrium. The envelope of the balloon has a mass of 0.250 kg. The density of helium is 0.179 kg/m 3 and atmospheric pressure is 1.013 X 10 5 Pa. What is the height h? air =1.29 kg m 3 He =0.179 kg m 3