Mechanical_lab

Mechanical_lab - Name: Date of lab: _ _ Section number: M E...

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Name: ______________________________________________ Date of lab: ______________________ Section number: M E 345._______ Lab 11 Precalculations – Individual Portion Mechanical Measurements Lab: Measurement of Mechanical Quantities Precalculations Score (for instructor or TA use only): _____ / 20 1. In the eddy current dynamometer setup, a clever device is used to directly measure torque. As seen in the sketch to the right, mass m is attached to a wheel of radius R , and is lifted up as torque T applied is applied (counterclockwise) to the wheel. Gravity provides a constant downward force Wm g = , but the moment arm (torque arm) r increases as the weight moves up in elevation, causing an increase in the counteracting (clockwise) torque T counteracting . The wheel is stationary when applied counteracting TT T = Weight, W R r θ T counteracting T applied Mass, m = , which is read directly on the torque scale built into the instrument. Derive an expression for torque T as a function of weight W , radius R , and angular displacement , showing all your algebra for full credit. 2. From the analysis above, does torque increase linearly or nonlinearly with angular displacement ? Explain. 3. The scale on the eddy current dynamometer torque gage reads torque in units of oz-in (force in ounces multiplied by moment arm in inches). If the reading is 130. oz-in, what is the torque in Newton-meters? If the shaft rotation rate is 1750 rpm, calculate the shaft power in watts. For full credit, show all your work, including unit conversions for both calculations. Note : Save your equations, because you will need them to do this lab .
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Cover Page for Lab 11 Lab Report – Group Portion Mechanical Measurements Lab: Measurement of Mechanical Quantities Name 1: ___________________________________________________ Section M E 345._______ Name 2: ___________________________________________________ Section M E 345._______ Name 3: ___________________________________________________ Section M E 345._______ [Name 4: ___________________________________________________ Section M E 345._______ ] Date when the lab was performed: ______________________ Group Lab Report Score (For instructor or TA use only) : Lab experiment and results, plots, tables, etc. _____ / 50 Discussion _____ / 20 Neatness & grammar _____ / 10 TOTAL ______ / 80 Comments (For instructor or TA use only) : NOTE: The instructor or TA reserves the right to deduct points for any of the following: Arriving late to lab or leaving before your lab group is finished. Not participating in the work of your lab group (freeloading). Causing distractions, arguing, or not paying attention during lab. Other (at the discretion of the instructor or TA).
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Mechanical Measurements Lab: Measurement of Mechanical Quantities Author: John M. Cimbala, Penn State University Latest revision: 04 December 2007 Introduction and Background ( Note : To save paper, you do not need to print this section for your lab report.) Instruments of various kinds have been invented to measure mechanical quantities , such as position (or displacement), velocity, angular velocity, acceleration, force, torque, and shaft power. Many of these instruments are discussed in detail in the class notes. In this lab, you get some hands-on experience with several of these instruments.
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This note was uploaded on 07/23/2008 for the course ME 345 taught by Professor Staff during the Spring '08 term at Penn State.

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Mechanical_lab - Name: Date of lab: _ _ Section number: M E...

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