Forces in Engineering

Question 1

Vector quantity referring to the change in velocity with a change in time (m/s2)
It can be calculated as: final velocity minus initial velocity (measured in m/s) divided by final time minus in- itial time

Answer 1

acceleration

Question 2

Angular separation between two objects as perceived by an observer (Source: www.thefreedictionary.- com/angular distance)

Answer 2

angular distance

Question 3

Forces which cause a structural element to bend under strain

Answer 3

bending forces

Question 4

Amount of stress a material can withstand before breaking

Answer 4

breaking strength

Question 5

Property of a material, which does not bend under strain and breaks easily when a mechanical shock is ap- plied for example.
illustration ductile vs. brittle: https://www.youtube.com/watch?v=JFSn_XsAvho

Answer 5

brittleness

Question 6

result of flexion bending forces applied onto an object

Answer 6

buckling

Question 7

Point through which the result of the weight of all the particles of the body acts

Illustration by TutorVista.com: https://www.youtube.com/watch?v=R8wKV0UQtlo

Answer 7

centre of gravity

Question 8

Forces which cause a structural element, which withstand the strain, to decrease in size or in volume e.g. decrease in length and cross section

Answer 8

compressive forces

Question 9

permanent or non permanent change in shape, which is often described in terms of strain, due to an app- lied force (e.g. bending f., compressive (pushing) forces (twisting), tensile (pulling) forces, or shear forces, torsion

Answer 9

deformation

Question 10

measure of the amount of matter contained by a given volume

Answer 10

density

Question 11

mechanical property of metal to stretch under certain conditions of heat, pressure and tensile forces in or- der to be drawn into wire.

illustration ductile vs. brittle: https://www.youtube.com/watch?v=JFSn_XsAvho

Answer 11

ductility

Question 12

Non permanent changing in shape (e.g. stretch or increase in length) due to a tensile force

Answer 12

elastic deformation

Question 13

Property by virtue of which a material deformed under the load but can regain its original dimensions when unloaded

Answer 13

elasticity

Question 14

Forces, which cause buckling

Answer 14

flexion bending forces

Question 15

influence that may cause a body to accelerate or change in shape. It may be experienced as a lift, a push, or a pull, and has a magnitude and a direction. The actual acceleration of the body is determined by the vec- tor sum of all forces acting on it
bending forces: Forces which cause a structural element to bend under strain
tensile forces: Forces which cause a structural element to stretch i.e. to increase in length while often to de- crease in cross section
compressive forces: Forces which cause a structural element which withstand the strain, to decrease in size or in volume e.g. decrease in length and cross section
flexion bending forces: Forces, which cause buckling
shear forces: Forces, which push in opposite direction at different points of the body
torsion forces: Forces which are resulting of applying a moment onto an object fasten to a wall for example.

Answer 15

force

Question 16

Force that opposes the relative motion or tendency toward such motion of two surfaces in contact. Engineers consider two main kind of friction:

• static friction and
• dynamic friction

Answer 16

friction

Question 17

property of a material or an object to resist most of the mechanical forces without deforming

Answer 17

hardness

Question 18

amount of matter contained by a given volume

Answer 18

mass

Question 19

Force multiplied by the perpendicular distance between the force and the pivot. It is often just ‘moment’, though there are other quantities of that name such as moment of inertia) is a quantity that represents the magnitude of force applied to a rotational system at a distance from the axis of rotation.

N.B.: Moment of a force is similar as ‘torque’

Answer 19

moment (of a force)

Question 20

Permanent deformation of material due to a force applied onto it

Answer 20

plastic deformation

Question 21

property of a solid body whereby it undergoes a permanent change in shape or size when subjected to a stress exceeding a particular value (the yield value)

Answer 21

plasticity

Question 22

movement of an object in a circular motion. A two-dimensional object rotates around a centre (or point) of rotation. A three-dimensional object rotates around a line called axis

Answer 22

rotation

Question 23

Forces, which push in opposite direction at different points of the body

Answer 23

shear forces

Question 24

scalar quantity with dimensions distance/time i.e scalar value expressing the rate of motion, or equivalent- ly the rate of change of position, many times expressed as distance d travelled per unit of time t.

Answer 24

speed

Question 25

a description of deformation in terms of relative displacement. Ratio of change in dimension relati- ve to the original dimension

3 types of strain :

• linear strain (ratio of change in length to the original length)
• volume or bulk strain (ratio of change in volume to the original volume)
• shearing strain is equal to the angle of shear

Answer 25

strain

Question 26

internal distribution of force per unit area that balances and reacts to external loads applied to a body

Answer 26

stress

Question 27

Forces which cause a structural element to stretch i.e. to increase in length while often to decrease in cross section

Answer 27

tensile forces

Question 28

The maximum amount of tension a material can withstand

Answer 28

tensile strength

Question 29

it is defined by linear force multiplied by a radius. It is often informally be thought of as “rotational force” or “angular force” which causes a change in rotational motion.
N.B. Similar notion as ‘moment’ or ‘moment of a force’

Answer 29

torque

Question 30

Forces which are resulting of applying a moment onto an object fasten to a wall for example

Answer 30

torsion forces

Question 31

the rate of change of the position of an object with respect to a frame of reference, and is a function of time

Answer 31

velocity

Question 32

Plastic deformation that occurs at a specific amount of stress (0,2% plastic strain)

Answer 32

Yield strength

Question 33

also called ‘modulus of elasticity’, Stiffness of the material when the material is undergoing deformation

Answer 33

Young’s modulus