48 Questions
What is the purpose of dynamic force analysis?
Evaluating input and joint forces in motion
How is the inertia force defined?
Opposite in magnitude to the accelerating force
What is the relationship between inertia force and linear acceleration?
Inertia force is independent of linear acceleration
What does the inertia torque represent?
Torque causing rotational acceleration
How can a system of forces acting on a rigid body be represented?
By a couple and a parallel force
In what direction does the force passed through the center of gravity act?
Parallel to the resultant force
What is the term used to describe the curve traced by a particle while moving along a screw thread?
Helix
Which type of screw threads are mainly used for tightening pieces together like bolts and nuts?
V-threads
What is the relationship between pitch, lead, and number of threads in a single-threaded screw?
Lead = Pitch × Number of threads
Which principle states that the resultant force acting on a body and the reversed effective force are in equilibrium?
D-Alembert's Principle
What is the inertia force described as in D-Alembert's Principle?
Reversed effective force
Which device works on a principle similar to that of an inclined plane for lifting heavy loads?
Screw Jack
What is the product of mass and linear acceleration of the center of mass of a body according to D-Alembert's Principle?
$m \cdot a$
Which type of screw threads offer more frictional resistance and prevent nuts from slackening?
V-threads
What is the slope or inclination of the thread with the horizontal known as?
Helix angle
What does FI represent in D-Alembert's Principle?
Inertia force
What is the total thrust from the propeller in Example 1?
100 kN
What is the torque required to lift a load by a screw jack if the pitch of the screw is represented by p, mean diameter by d, helix angle by a, effort applied at the circumference by P, load to be lifted by W, and coefficient of friction by µ?
$W \tan (a+f)$
In Example 2, what power is absorbed when the shaft runs at 105 r.p.m. carrying a load of 150 kN under uniform pressure?
13.64 kW
In the context of a square threaded screw, what is the normal reaction given the helix angle a?
$W \cos a$
In the context of collar bearings, what is the external diameter of the collars in Example 1?
600 mm
What is the total torque required to overcome friction in a turning pair if an effort P1 is applied at the end of a lever of arm length l?
Equal to the torque applied at the end of the lever
In a journal bearing, what forms a line contact when not lubricated?
The lubricant layer
What does the coefficient of friction value of 0.12 represent in the context of collar bearings?
Frictional force
What angle is represented by 2 in the context of V-thread?
Angle of the V-thread
What does the variable 'n' represent in the given context of collar bearings examples?
Number of collars required
How is the speed of rotation (N) related to angular velocity (ω) in the provided text?
$2π × N$
How is the normal reaction calculated for V-thread where the axial component must be equal to the axial load W?
$W\cos 2$
What is NOT true about the torque required to overcome friction between the screw and nut?
$\frac{R_1 + R_2}{R}$
What happens to the reaction R in a journal bearing when lubricated?
It acts at 'Point A'
What is assumed to be proportional for the rate of wear in rubbing surfaces?
The product of intensity of pressure and velocity of rubbing surfaces
What is the formula for the vertical load acting on a small ring of radius r along a cone?
$dW = dW_n \sin a$
In the context of uniform wear, what is the relationship between the intensity of pressure and the distance from the central axis?
$p_r = C / r$
What is the formula for the total frictional torque acting on a conical pivot bearing?
$T_r = \int p_n \times 2 \pi r , dr$
When using a trapezoidal or truncated conical pivot bearing, what is considered to be uniform?
Pressure distribution
What is the total torque acting on a bearing obtained by integrating the value of $T_r$ within the limits between $r_1$ and $r_2$?
$T = \int_{r_1}^{r_2} T_r , dr$
For a collar bearing, what is its primary function?
To carry vertical loads
What is the coefficient of friction assumed in Example 1 concerning power lost in friction?
$0.05$
In Example 1, if the shaft diameter is given in millimeters, what is its equivalent value in meters?
$0.075$ m
What is the total power absorbed in friction for the conical pivot bearing supporting a load of 20 kN with a cone angle of 120º?
$6.322$ kW
What is the coefficient of friction represented by in the given text?
ø
In the context provided, what does the angle ø represent?
The angle between the resultant force and RN
Which type of pivot may have a flat surface or conical surface?
Flat pivot
What type of bearing is typically used in modern practice for large thrusts, like in propeller shafts of ships?
Thrust bearings
What parameter determines the rate of wear according to the given text?
Velocity of rubbing surfaces
In the context provided, what is represented by T = W.rtanø?
Frictional torque
What does a truncated pivot represent?
A pivot with a cone that is cut off
What does wear being uniform throughout the bearing surface imply?
"Different radii experience different rates of wear."
Test your knowledge on static force analysis and dynamic force analysis, focusing on evaluation of input forces, joint forces, and inertia forces. Understand the differences between static and dynamic force analysis.
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