Static and Dynamic Force Analysis Quiz
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Questions and Answers

What is the purpose of dynamic force analysis?

  • Studying the equilibrium positions
  • Determining the accelerating couple
  • Calculating the inertia force
  • Evaluating input forces or torques (correct)

    • How is the inertia force defined?

  • An imaginary force bringing a rigid body to an equilibrium position
  • Mathematically expressed as F x h
  • Opposite in magnitude and direction to the accelerating force (correct)
  • Equal to the accelerating couple in magnitude and direction

    • What is the relationship between inertia torque and accelerating couple?

  • They have the same magnitude and direction
  • They are mathematically expressed as F x h
  • Inertia torque is equal to the accelerating couple in direction
  • Opposite in magnitude but equal in direction (correct)

    • How can a system of forces acting on a rigid body be reduced?

    <p>To a single resultant force and a couple</p> Signup and view all the answers

    What creates a couple on a rigid body?

    <p>Two equal and opposite forces acting through the center of gravity</p> Signup and view all the answers

    What is the inertia torque?

    <ul> <li>Imaginary torque bringing a rigid body to equilibrium</li> </ul> Signup and view all the answers

    What term describes the distance a screw thread advances axially in one turn?

    <p>Lead</p> Signup and view all the answers

    Which type of thread is stronger and offers more resistance to motion than square threads?

    <p>V-threads</p> Signup and view all the answers

    What is the principle on which a screw jack works similar to?

    <p>Inclined plane</p> Signup and view all the answers

    What is the curve traced by a particle moving along a screw thread at a uniform speed?

    <p>Helix</p> Signup and view all the answers

    Which type of screw threads are generally used for tightening pieces like bolts and nuts together?

    <p>V-threads</p> Signup and view all the answers

    What term refers to the difference between the top and bottom surfaces of a screw thread?

    <p>Depth of thread</p> Signup and view all the answers

    What does D-Alembert's principle state about the resultant force and inertia force?

    <p>They are in equilibrium.</p> Signup and view all the answers

    What is the equivalent static problem obtained from reducing a dynamic problem using D-Alembert's principle?

    <p>Reduced to a single resultant force acting on the body.</p> Signup and view all the answers

    Which type of screw threads are used in screw jacks and vice screws?

    <p>Square threads</p> Signup and view all the answers

    What does the equation F + FI = 0 represent in D-Alembert's principle?

    <p>Resultant force equals reversed effective force.</p> Signup and view all the answers

    What is the main function of a screw jack?

    <p>To lift or lower a load</p> Signup and view all the answers

    In the context of a screw jack, what does the coefficient of friction µ represent?

    <p>The friction between the screw and nut</p> Signup and view all the answers

    What is the relationship between the effort applied (P) and the load (W) in a screw jack?

    <p>$P = W \times \tan(a+f)$</p> Signup and view all the answers

    When using a V-thread, how does the normal reaction between the screw and nut differ compared to a square threaded screw?

    <p>It is equal to the axial load W</p> Signup and view all the answers

    In a journal bearing, what happens when there is no lubrication present?

    <p>A greasy friction occurs with line contact</p> Signup and view all the answers

    What is the purpose of a thrust collar in relation to a screw jack?

    <p>To prevent the load from rotating with the screw</p> Signup and view all the answers

    How does the total torque required to rotate a screw change when an effort P1 is applied at the end of a lever?

    <p>$P1$ increases the torque required</p> Signup and view all the answers

    What force does a screw jack leverage to lift or lower a load?

    <p>$F = P \times \cos(a)$</p> Signup and view all the answers

    How does friction change between a screw and nut when using a V-thread instead of a square threaded screw?

    <p><code>$f$ increases due to increased surface area</code></p> Signup and view all the answers

    What is the role of the frictional force F in relation to the shaft rotation?

    <p>Acts at the circumference of the shaft to rotate it in the opposite direction</p> Signup and view all the answers

    What must be true for the resultant force acting on the shaft for uniform motion?

    <p>It must be zero</p> Signup and view all the answers

    In terms of resultant turning moment on the shaft, what condition is necessary for uniform motion?

    <p>It must be zero</p> Signup and view all the answers

    What is the relationship between T (frictional torque) and ø according to the provided text?

    <p>$T = W \times r \tan{\theta}$</p> Signup and view all the answers

    What is used to take the axial thrust of rotating shafts like those in ships and turbines?

    <p>Ball and roller thrust bearings</p> Signup and view all the answers

    What condition is assumed in the study of bearing friction as per the text?

    <p>The pressure is uniformly distributed throughout the bearing surface</p> Signup and view all the answers

    When a vertical shaft rotates in a flat pivot bearing, where does the sliding friction occur?

    <p>Along the surface of contact between the shaft and bearing</p> Signup and view all the answers

    'Truncated or trapezoidal pivot' terminology refers to what kind of pivot?

    <p>&quot;Pivot with a truncated cone as bearing&quot;</p> Signup and view all the answers

    'Foot step bearing' terminology commonly refers to which type of pivot bearing?

    <p>&quot;Flat pivot bearing&quot;</p> Signup and view all the answers

    What is considered when there is uniform pressure in a flat pivot bearing?

    <p>Wear rate depends on velocity and intensity of pressure.</p> Signup and view all the answers

    What is another name for collar bearings?

    <p>Thrust bearings</p> Signup and view all the answers

    In the context of collar bearings, what does the symbol r1 represent?

    <p>External radius of the collar</p> Signup and view all the answers

    What does the coefficient of friction of 0.12 refer to in the context of collar bearings?

    <p>Intensity of pressure</p> Signup and view all the answers

    When considering uniform wear in collar bearings, what does the total load transmitted to the collar represent?

    <p>Total frictional torque on the collar</p> Signup and view all the answers

    What does the symbol d1 = 600 mm or r1 = 300 mm represent in Example 1?

    <p>External diameter of the collars</p> Signup and view all the answers

    What does the intensity of pressure of 0.35 N/mm2 refer to in Example 2?

    <p>Load carried by the shaft</p> Signup and view all the answers

    What is the assumption made about the rate of wear in bearings?

    <p>It is proportional to the product of intensity of pressure and velocity.</p> Signup and view all the answers

    What is the formula for power lost in friction given the coefficient of friction and load?

    <p>$P = \mu \times W \times N$</p> Signup and view all the answers

    In the context of bearings, what does 'dl' represent?

    <p>The length of the ring along the cone.</p> Signup and view all the answers

    What does 'C/r' represent in the context of uniform wear in bearings?

    <p>A measure of intensity of pressure</p> Signup and view all the answers

    What is the formula for total torque acting on a conical pivot bearing?

    <p>$T = \int_{r1}^{r2} pn\cdot A,dr$</p> Signup and view all the answers

    In a frustum bearing, what does '2pC.dr' represent?

    <p>The load transmitted to the ring.</p> Signup and view all the answers

    What does '301.76' represent in calculating the power absorbed in friction?

    <p>$\mu$ (coefficient of friction)</p> Signup and view all the answers

    How is 'dl' related to 'dr' in bearing calculations?

    <p>'dl' is a function of 'dr'.</p> Signup and view all the answers

    What information does 'pn × 2pr.drcosec a' provide?

    <p>Normal load acting on the ring.</p> Signup and view all the answers

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