Physics exam 3
12. The pressure exerted by a phonograph needle on a record is surprisingly large. If the equivalent of 1.00 g is supported by a needle, the tip of which is a circle 0.200 mm in radius, what pressure is exerted on the record in N/m2size 12{"N/m" rSup { size 8{2} } } {}
.001*9.8/pi .0002 squared 7.8x10^4 Pa
11. A tire has a tread pattern with a crevice every 2.00 cm. Each crevice makes a single vibration as the tire moves. What is the frequency of these vibrations if the car moves at 30.0 m/s?
1500 hz
49. Wind gusts create ripples on the ocean that have a wavelength of 5.00 cm and propagate at 2.00 m/s. What is their frequency?
2/.05=40hz
2. Mercury is commonly supplied in flasks containing 34.5 kg (about 76 lb). What is the volume in liters of this much mercury?
34.5/13,600=.0025 *1ooo 2.5 liters
17. Water towers store water above the level of consumers for times of heavy use, eliminating the need for high-speed pumps. How high above a user must the water level be to create a gauge pressure of 3.00×105N/m2size 12{3 "." "00" times "10" rSup { size 8{5} } `"N/m" rSup { size 8{2} } } {}?
3x10^5=1000(9.8)h 30.6m
6. Air temperature in the Sahara Desert can reach 56.0ºC (about 134ºF). What is the speed of sound in air at that temperature?
56+ 273=329 329/273 root *331
18. A diver on a diving board is undergoing simple harmonic motion. Her mass is 55.0 kg and the period of her motion is 0.800 s. The next diver is a male whose period of simple harmonic oscillation is 1.05 s. What is his mass if the mass of the board is negligible?
94,8 kg
24. What is the period of a 1.00-m-long pendulum?
easy 2pi sq root 1/9.8
33. A small artery has a length of 1.1×10−3m and a radius of 2.5×10−5m. If the pressure drop across the artery is 1.3 kPa, what is the flow rate through the artery? (Assume that the temperature is 37º.)
idk
19. (a) What is the intensity of a sound that has a level 7.00 dB lower than a 4.00×10-9W/m2 sound? (b) What is the intensity of a sound that is 3.00 dB higher than a 4.00×10-9W/m2 sound?
logss
49. What fraction of an iron anchor's weight will be supported by buoyant force when submerged in saltwater?
lower/bigger *100= 1025/7800= .13 13%
19. If the pressure reading of your pitot tube is 15.0 mm Hg at a speed of 200 km/h, what will it be at 700 km/h at the same altitude?
no clue -22,409 pa
#4 Blood is flowing through an artery of radius 2 mm at a rate of 40 cm/s. Determine the flow rate and the volume that passes through the artery in a period of 30 s.
pi*.2 squared**40 5cmsq/s b) 5x30=150
26. An 8-hour exposure to a sound intensity level of 90.0 dB may cause hearing damage. What energy in joules falls on a 0.800-cm-diameter eardrum so exposed?
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