Theory and Design for Mechanical Measurements
6th Edition
ISBN: 9781118881279
Author: Richard S. Figliola, Donald E. Beasley
Publisher: WILEY
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 5, Problem 5.13P
Heat transfer from a rod of diameter D immersed in a fluid can be described by the Nusselt number. Nu = hD/k. where h is the heat-transfer coefficient and k the thermal conductivity of the fluid. If h can be measured to within ±1% (95%), estimate the uncertainty in Nu for the nominal value of h = 150 W/nr-K. Let D= 20 ±0.5 mm and k = 0.6 ± 2% W/m-K.
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
A company that manufacturers gas cylinder is interested in assessing the relationship between pressure dependent variable and volume of the gas independent variable. The table below gives experimental values of pressure of a given mass of gas corresponding to various of the volume. According to the thermodynamic principles, the relationship be of the form of
PVy=C
where y and C are constants
Volume 53.3 61.8 72.4 88.7 119 194
Pressure 61.2 49.5 37.6 28.4 19.2 10
Find the values y and c that best fit the data
The heat transfer between a solid body and a fluid medium is determined by the equation Q=h·A·(Ts-Tf). Here; Q is the amount of heat transferred, h is the heat transfer coefficient, A is the heat transfer surface area, Ts is the temperature of the surface and Tf is the temperature of the fluid. These parameters were measured as h=250±1.75 W/m2ºC, A=20±0.75 m2, Ts =100±0.75ºC and Tf =25±0.75ºC, including error levels. What is the total uncertainty in the amount of heat transferred, in ±%?
a. 3.98
b. 4.07
c. 2.73
d. 2.95
e. 3.88
To measure the density of a stone, a digital scale and a beaker cup filled with water are used. The balance is used to measure the mass of the stone, while the beaker is used to measure the volume of the stone. It is known that the digital balance has a resolution of 0.1 g and that the beaker cup has a resolution of 5 ml. Repeated mass measurements return the following values: 250.0 g; 249.9 g; 250.3 g; 249.6g; 250.1 g; 249.7g; 250.4 g; 250.0 g; 248.8 g; 250.2 g The volume is measured only once. Placing the stone in the beaker, a volume of displaced water equal to 50 ml is measured. Using a k=2.5, check if the density of the stone is compatible or out of line with the value ρ = (4910 ± 65) kg.m-3
(a) none of the above
(b) the values are compatible
(c) missing data to perform the compatibility test
(d) the values are discrepant
Chapter 5 Solutions
Theory and Design for Mechanical Measurements
Ch. 5 - Prob. 5.1PCh. 5 - Explain what is meant by the terms “true value,"...Ch. 5 - SJ An official Olympics timekeeper once stated,...Ch. 5 - A tachometer has an analog display dial graduated...Ch. 5 - An automobile speedometer is graduated in 5-mph...Ch. 5 - An engineer reads the height of a mercury...Ch. 5 - Prob. 5.8PCh. 5 - Two resistors arc to be combined to form an...Ch. 5 - An equipment catalog boasts that a pressure...Ch. 5 - The shear modulus, G, of an alloy can be...
Ch. 5 - Heat transfer from a rod of diameter D immersed in...Ch. 5 - Estimate the design-stage uncertainty in...Ch. 5 - Explain the critical dift'erence(s) between a...Ch. 5 - A displacement transducer has the following...Ch. 5 - Prob. 5.18PCh. 5 - For a thin-walled pressure vessel of diameter D...Ch. 5 - Suppose a measured normal stress contains three...Ch. 5 - Prob. 5.31PCh. 5 - The area of a flat, rectangular parcel of land is...Ch. 5 - Estimate the random standard uncertainty in the...Ch. 5 - Estimate the uncertainty at 95% confidence in the...Ch. 5 - One use for a GPS rangefinder is on the golf...Ch. 5 - A pressure measuring system outputs a voltage that...Ch. 5 - The density of a metal composite is to be...Ch. 5 - A temperature measurement system is calibrated...Ch. 5 - The power usage of a strip heater is to be...Ch. 5 - The power usage of a DC strip heater can be...Ch. 5 - A thermocouple is a temperature sensor made of two...Ch. 5 - Time variations in a signal require that the...Ch. 5 - A hand-held infrared thermometer from a well-...Ch. 5 - The pressure in a large vessel is to be maintained...Ch. 5 - The cooling of a thermometer (c.g., Exs. 3.3 and...Ch. 5 - A J-type thermocouple monitors the temperature of...Ch. 5 - The density of air must be known to within 0.5%....Ch. 5 - In pneumatic conveying, solid particles such as...Ch. 5 - A step test is run to determine the time constant...Ch. 5 - The acceleration of a cart down a plane inclined...Ch. 5 - The heat flux in a reaction is estimated by Q =...Ch. 5 - A comparative test uses the relationship R =...Ch. 5 - A sensitive material is to be contained within a...Ch. 5 - A geometric stress concentration factor, K,, is...Ch. 5 - In Problem 5.9, we assumed that the errors in die...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- The following resistance of a platinum resistance thermometer were measured at a range of temperature. Determine the measurement sensitivity of the instrument in milli Ohms/ oC. Resistance (mῼ) Tempreture (oC) 210k 110 217k 89 221k 68 228k 47arrow_forwardThe shear modulus, G, of an alloy can be determined by measuring the angular twist, θ,resulting from a torque applied to a cylindrical rod made from the alloy. For a rod of radius Rand a torque applied at a length L from a fixed end, the modulus is found by G=2LT/pR4θ.Examine the effect of the relative uncertainty of each measured variable on the shearmodulus. If during test planning all of the uncertainties are estimated to be 1%, what is theuncertainty in G?arrow_forwardThe transducer specified in Table 1.1 is chosen to measurea nominal pressure of 500 cm H2O. The ambient temperature is expected to vary between 18 ∘C and 25 ∘C duringtests. Estimate the possible range (magnitude) of each listedelemental error affecting the measured pressure refering to the solution provided online, Sensitivity error(eK) = (±0.0025)(500 cm H2O)= ± 0.75 cm H2O = ± 0.00375 V how do you get 0.75?? shoud it not be 1.25? according the answer, for sensitivityarrow_forward
- Voltage E = 220 V ± 1% and resistance R = 22 W ± 0.5% were measured in an electrical circuit with measuring devices. What is the uncertainty in calculating the electrical power expressed as P = E2 / R? A)%2.45 B)%2.53 C)%2.24 D)%2.35 E)%2.64arrow_forwardA core was mounted in a gas permeameter to measure permeability. Determine the liquid permeability (mD) of the core using gas (in oilfield units). The laboratory data are as follows: Diameter of the core = 3.78 cm Length of the core = 7.63 cm Gas viscosity = 0.0148 cP Flow rate = 9.07 cm3/s P1 = 1.439 atm P2 = 1.086 atmarrow_forwardThe actual value of pressure differential for flow across a venturimeter is 60 mm WC. The measured values using a pressure sensor are; Confidence level 95% mm WC 59.8,59.2,59.7,60.2,60.3,60.1,60.5 Estimate Bias uncertainty (1) Precision uncertainty (2) Total uncertainty (3)arrow_forward
- A thermoeleman circuit given as voltage-temperature correlation E=a·T will measure the temperature in an environment, T1 = 290ºC > T2 > T3 = 0ºC. This thermoeleman produces a voltage of 16.32 mV at (T1-T3) temperature awareness and 15.3 mV at (T1-T2) temperature awareness. How many ºC is T2 temperature? a. 18.64 b. 18.75 c. 20.00 d. 19.97 e. 18.13arrow_forwardThe transducer specified in Table 1.1 is chosen to measurea nominal pressure of 500 cm H2O. The ambient temperature is expected to vary between 18 ∘C and 25 ∘C duringtests. Estimate the possible range (magnitude) of each listedelemental error affecting the measured pressure. How do I calculate the sensitivity error? The solution that was given: Sensitivity error(eK) = (±0.0025)(500 cm H2O)= ± 0.75 cm H2O = ± 0.00375 V My Question is, how do you obtain 0.75 since 0.0025 x 500 gives 1.25! please help. thanksarrow_forwardA mercury barometer at the top of a mountain reads 700 mmHg and at the same time the barometer at its base reads 800 mmHg. If the unit weight of air is 12 N/m3 and specific gravity of mercury is 13.6, what is the approximate height (in meters) of the mountain?a. 1111.8 b. 113.33 c. 1.1118 d. 0.1133arrow_forward
- Calculate the absolute uncertainty, fractional uncertainty, and percentile uncertaintyarrow_forwardThe same engineer decides to look into rates of cooling for liquids toexperiment with different cooling solutions for servers. She finds thatthe rate of cooling for one liquid can be modelled by the equation:y = 48 × 0.99t(0 ≤ t ≤ 80)where y is the temperature of the liquid in degrees Celsius and t is thetime in minutes.(i) State whether the type of reduction for this model is linear orexponential. Describe how reduction rate differs between linear andexponential functions. (ii) Calculate the temperature when t = 20. [3](iii) Write down the scale factor and use this to find the percentagedecrease in the temperature per minute. (iv) Use the method shown in Subsection 5.2 of Unit 13 to find the timeat which the temperature is 30◦(v) Determine the halving time of the temperature.arrow_forwardIn a dead weight tester experiment, theoretical pressure is 4 bar, error is 0.04997% , then its approximate measured pressure is __________ A. 16 bar B. 1600000 N/m2 C. None of the answers given D. 2 bararrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning
Principles of Heat Transfer (Activate Learning wi...
Mechanical Engineering
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Cengage Learning
Understanding Conduction and the Heat Equation; Author: The Efficient Engineer;https://www.youtube.com/watch?v=6jQsLAqrZGQ;License: Standard youtube license