Master Physics with Fun Quizzes & Brain Teasers!

An object is thrown upward from a height of 7ft. The height h of the object (in feet) t sec after the object is released is given by h = -16t2 + 48t + 7. Round your answers to two decimal places, if necessary.
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The following data gives stopping potential V0 versus wavelength for photoelectrons produced from a metal surface. (Be sure to include the correct units and use three significant figures.)Table 1(nm)V0(volts)5021.31009.331505.182003.152501.913001.07Use an analysis similar to that used in the inlab procedure to determine the work function (in eV) for this surface. (Use1 eV = 1.602 1019 J,e = 1.602 1019 C,c = 2.998 108 m/s,andh = 6.626 1034 J s = 4.136 1015 eV sas necessary.)
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what will be the current when the capacitor has acquired 1/4 of its maximum charge? ii = nothing aa
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at what temperature does a process with [delta]h = 30. kj and [delta]s = 900. j become spontaneous?
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a disk of radius 11 cm, initially at rest, begins rotating about its axis with a constant angular acceleration of 7 rad/s2. what are the following values at t = 6 s?
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An astronomer is interested in measuring the distance, in light years, from his observatory to a distant star. Although the astronomer has a measuring technique, it is known that, because of changing atmospheric conditions and normal error, each time a measurement is made it will not yield the exact distance but merely an estimate. As a result, the astronomer plans to make a series of measurements and then use the average value of these measurements as the estimated value of the actual distance. If the astronomer believes that the values of the measurements are independent and identically distributed random variables having a common mean (the actual distance) and a common variance of 4 light years,(a) how many measurements are needed to be 95 percent sure that the estimated distance is accurate to within 0.5 light years using the central limit theorem?(b) Answer the question in part (a) using Chebyshev's inequality.
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what is the wavelength of a 4.5 ghz wifi signal?
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Definition of CapacitanceTwo conductors having net charges of +10.0C and 10.0C have a potential difference of 10.0V between them.(a) Determine the capacitance of the system.(b) What is the potential difference between the two conductors if the charges on each are increased to +100C and 100C?
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Using the Bohr model, what is the energy in joules of the photon produced when an electron in a He* ion moves from the orbit with n = 5 to the orbit with n = 2?
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Gold, which has a density of 19.32 g/cm3, is the most ductile metal and can be pressed into a thin leaf or drawn out into a long fiber. (a) If a sample of gold with a mass of 1.365 g, is pressed into a leaf of 7.696 um thickness, what is the area (in m2) of the leaf? (b) If, instead, the gold is drawn out into a cylindrical fiber of radius 2.600 um, what is the length (in m) of the fiber?
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a dad pushes tangentially on a small hand-driven merry-go-round and is able to accelerate it from rest to a frequency of 15 rpm in 13.0 s . assume the merry-go-round is a uniform disk of radius 2.5 m and has a mass of 560 kg , and two children (each with a mass of 25 kg ) sit opposite each other on the edge.
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an astronaut, whose mission is to go where no one has gone before, lands on a spherical planet in a distant galaxy. as she stands on the surface of the planet, she releases a small rock from rest and finds that it takes the rock 0.460 s to fall 1.90 m .
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Suppose the race car now slows down uniformly from 60.0 m/s to 30.0 m/s in 4.50 s to avoid an accident, while still traversing a circular path 4.00 102 m in radius. Find the cars (a) centripetal acceleration, (b) angular speed, (c) tangential acceleration, and (d) total acceleration when the speed is 40.0 m/s.
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suppose that water waves coming back into a dock have a velocity of 2.1 m/s and a wavelength of 5.6 m. with what frequency do these waves meet the dock
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when the static modifier is placed on a c local variable, what does it change?
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In an L-R-C series circuit, L=0.280 H and C=4.00\mu F. The Voltage amplitude of the source is 120 V.A) what is the resonance angular frequency of the circuit?B) When the source operates at the resonance angular frequency, the current amplitude in the circuit is 1.70 A. What is the resistance R of the resistor?C) At the resonance angular frequency, what are the peak voltages across the inductor, the capacitor, and the resistor?
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what is the entropy change in a process that brings the gas to 550 k and 1.3 atm ?
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Once dark adapted, the pupil of your eye is approximately 7 mm in diameter. The headlights of an oncoming car are 120 cm apart. If the lens of your eye is diffraction limited, at what distance are the two headlights marginally resolved? Assume a wavelength of 565nm and that the index of refraction inside the eye is 1.33. (Your eye is not really good enough to resolve headlights at this distance, due both to aberrations in the lens and to the size of the receptors in your retina, but it comes reasonably close.) (km)
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A battery having an emf (voltage) of 9.00 V delivers 117 mA when connected to a 72 load. What is the internal resistance of the battery?
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a 183 cm string clamped at both ends under a tension of 310 n has a fundamental frequency of 351 hz (the note f). what is the frequency of the third harmonic?
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A 15.0-F capacitor is charged by a 150.0-V power supply, then disconnected from the power and connected in series with a 0.260-mH inductor.a) Calculate the oscillation frequency of the circuit.b) Calculate the energy stored in the capacitor at time t=0 ms (the moment of connection with the inductor).c) Calculate the energy stored in the inductor at t = 1.30 ms.
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if the outside air pressure decreases, the reading on a tire gauge connected to a tire also decreases.T/F
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When you blow across the opening of a partially filled two-liter soda pop bottle you hear a tone. If you take a sip of the pop and blow across the opening again, does the tone you hear have a higher frequency, a lower frequency, or the same frequency as before?1.higher frequency2.lower frequency3.the same frequencyExplain.
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A 21-tooth pinion rotating at 1500 rpm meshes with a 35- tooth gear in a sour gear reducer. Both pinion and cear are manufactured to a quality level of 9. A reliability of 0.9 hasbeen specified and the transmitted tangential load is 10 kN.Conditions are such that Ay = 1.7. It is proposed that standard 25 tull-depth teeth be used, with both pinion and gear hobbed from an AISI 4140 nitnided steel. The module is 4 and the face width 50 mm. Assume that the life of the oinion will be less than that of the gear. Assume the lubricant bulk temperature does not exceed 250F, both driver and driven devices are smcom-running. gears are sold disc. Use the averace value for the uncorrected bendina-fatigno strength. Assume that the reducer is used for critical serviceapplicationsCalculate the bending stress
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