Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

IT ERA > Mach Elem > Flashcards

Mach Elem Flashcards

1
Q

particles composing the body are equal and parallel

A

translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

It is necessary to know the velocity of only one particle in order to find the velocity of any other particle.

A

Velocities in Machines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

It is necessary to have enough data to determine the velocity of two particles in order to determine the velocity of any part of the body.

A

coplanar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Analyzing velocity of a rigid body, point and particle will be used interchangeably.

A
  • two or more points on the same body
  • points on two or more bodies connected by pin joints
  • points on bodies in rolling contact
  • points on bodies in sliding contact
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Velocities and accelerations in machines may be quite complicated, impossible.

A

Analytical analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Velocities and accelerations in machines may be more direct, less complicated, and usually sufficiently accurate.

A

Graphical analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Four commonly used methods for obtaining velocities:

A
  1. Resolution and composition
  2. Instantaneous axis of velocity
  3. Centro
  4. Relative velocity or velocity polygon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

give the quickest solution methods for obtaining velocities

A
  1. Resolution and composition
  2. Instantaneous axis of velocity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

can be used in the solution of practically all problem and the most desirable method

A

. Relative velocity or velocity polygon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

quantity has magnitude only

A

scalar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

has magnitude, direction, and sense

A

A vector quantity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

represents a vector quantity

A

vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The sum of the quantities is called

A

resultant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The sum of the quantities and its vector

A

resultant vector.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The quantities added together to obtain the resultant are its

A

components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The quantities added together to obtain the resultant, and the corresponding vectors are the

A

component vectors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The process of obtaining the resultant of any number of vectors is called

A

vector composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

reverse process of breaking up a vector into components is called

A

vector resolution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

It is necessary to draw the machine full scale, to a smaller scale, or to a larger scale

A

Scales

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

It is necessary to draw the machine full scale, to a smaller scale, or to a larger scale, This _______ is expressed in three ways

A

space scale

21
Q

space scale is expressed in three ways:

A
  1. Proportionate size, eg (¼ scale, 1:2)
  2. Number of inches on the drawing equal to 1 foot on the machine, eg (3 in. = 1 ft)
  3. 1 inch on the drawing equals so many feet, eg (1 in. = ⅓ ft, 1 in. = 1/34 ft)
22
Q

designated Kv, defined as the linear velocity in the distance units per unit of time.

A

Velocity scale

23
Q

designated Ka, defined as the linear acceleration in distance units per unit of time per unit of time

A

Acceleration scale

24
Q

Magnitude of the instantaneous linear velocity of a point on a revolving body, rotating crank, or oscillating crank is proportional to the distance of that point from the axis of rotation of the body or crank.

A

Rotating and Oscillating Cranks

25
If the velocity of one point and the direction of the velocity of any other point on a body are known, the velocity of any other point on that body may be obtained by resolving the known velocity vector into components along and perpendicular to the line joining theses points and making one of the components of the velocity of the other point equal to the component along the line.
Resolution and Composition
26
Instantaneously this moving axis may be thought of as a stationary axis with properties similar to a fixed axis. In other words, The cranks of a machine rotate or oscillate about their respective fixed axes and
Instantaneous Axis of Velocity
27
A method for obtaining the instantaneous absolute angular velocity of a floating link.
Angular Velocity of a Floating Link
28
If a wheel rolls along the surface without slipping the point of contact of the wheel and the surface is the instantaneous axis of velocity and the entire wheel acts as if it were a crank rotating about the axis Q.
Instantaneous Axis of Rolling Bodies
29
the instantaneous axis of velocity method of obtaining velocities is a simplified version of the _____ method and can be used in obtaining velocities when the instantaneous axis can be located.
Centros
30
By using the method of _______, velocities in all mechanisms can be obtained.
Centros
31
A centro may be defined as:
1. A point common to two bodies having the same velocity in each 2. A point in one body about which another body actually turns 3. A point in one body about which another body tends to turn
32
is also the definition of an instantaneous axis of velocity
A point in one body about which another body tends to turn
33
All links, including the frame, are numbered as 1, 2, 3, and so on. A centro has a double number as 12, 13, 24, and so on.
Notation of Centros
34
The _______ in a mechanism is the number of possible combinations of the links taken two at a time.
Number of Centros
35
Number of Centros may be obtained by the equation
Number of centros = N(N - 1)/2 Where: N = number of links, including the frame, in the mechanism
36
Centros are located by:
1. Observation 2. The application of Kennedy’s theorem
37
which stated that any three bodies having plane motion relative to each other have only three centros which lie along the same straight line. In other words, the three centros that are akin to each other lie along the same straight line.
Location of Centros
38
Is used to determine the velocities of different points on links of a mechanism for a given input motion. Determination of the motion characteristics of links in a mechanism is required for the force analysis.
VELOCITY ANALYSIS
39
Velocities of links and of points of mechanism can be determined by different methods.
Relative velocity method or velocity polygon method Instantaneous center method.
40
an imaginary instantaneous point about when a link is assumed to rotate
Instantaneous center
41
Types of I-centers
Fixed Permanent Neither fixed nor permanent
42
Types of I-centers remain in same plane for all configurations.
Fixed
43
Types of I-centers moves when the mechanism moves
Permanent
44
Types of I-centers vary with the configuration of the mechanism.
Neither fixed nor permanent
45
The method of centros affords an excellent manner for determining the instantaneous angular velocity ratio of any two link and the instantaneous absolute angular velocity of any link when the instantaneous absolute angular velocity of one link in a mechanism
Angular Velocities of Links
46
All motions, strictly speaking, are relative motion in that some arbitrary set of axes or planes must be established in order that the motion may be defined. It is customary to assume that the earth is a fixed reference plane when analyzing the velocities and motion of machine members, and to refer to such motion as absolute motions.
Relative Velocity
47
A _______ in a machine, rotating about an axis fixed to the machine frame which is attached to a foundation in the earth has absolute motion
crank
48
A ______, the connecting rod of a machine, has motion relative to the crank.
floating link
49
The principles discussed in the preceding article afford a useful method of obtaining the instantaneous angular velocities of the members in a machine and the instantaneous linear velocities of points on these members.
Relative Velocity Method of Obtaining Velocities

IT ERA (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions