LECTURE #1 - forces and vectors

Question 1

what is forces ?

Answer 1

• effect that one boy has on another
• a push or pull applied to an object
• that required to change the state of motion of an object (i.e., that which causes acceleration)

Question 2

force (cause) →

Answer 2

acceleration (effect)

Question 3

whats an example of a vector ?

Answer 3

force

Question 4

what is force (push or pull) ?

Answer 4

causes deformation and / or motion

Question 5

what is force (vector quantity) ?

Answer 5

magnitude, direction and point of application

Question 6

what is the formula for force ?

Answer 6

F = ma

Question 7

what unit is force in ?

Answer 7

newtons (N)

Question 8

how to calculate a newton ?

Answer 8

mass x acceleration

Question 9

what is gravity ?

Answer 9

-9.81 m/s²

Question 10

what is the following referring to ?

“magnitude (size) and direction (orientation)”

Answer 10

force (a vector quantity)

Question 11

what is a third unique characteristic of force ?

Answer 11

point of application (especially important relative to the determination fo moments or torques)

Question 12

what are three characteristics of force ?

Answer 12

• magnitude
• direction
• point of application
• line of action
• angle of pull / orientation

Question 13

when classifying forces what are the two types of forces ?

Answer 13

internal and external forces

Question 14

what are internal forces ?

Answer 14

• refers to a force that acts within a system or object, influencing its internal components or elements
• these forces do not originate from external sources but result from interactions between different parts or elements within the system itself
• ex. muscle tension, ligament tension, bone compression

Question 15

what are external forces ?

Answer 15

• act on an object as result of interaction with environment
• can include pushes, pulls, or any other interactions that originate from sources outside the system being analyzed.

Question 16

what are contact forces ?

Answer 16

forces resulting from objects coming into contact

Question 17

what are non contact forces ?

Answer 17

forces that occur even if objects are not in contact

Question 18

what are some examples of non contact ?

Answer 18

gravity, magnetic, electrical

Question 19

what are two classifying forces ?

Answer 19

normal force and tangential force

Question 20

what is normal force ?

Answer 20

force acting perpendicular to surface of object

Question 21

what is an example of normal force ?

Answer 21

gravity pulling you down is an example

Question 22

what is tangential force ?

Answer 22

force action parallel to surface of object

Question 23

what is an example of tangential force ?

Answer 23

orientation is parallel

Question 24

what is contact force ?

Answer 24

A force that requires physical touch or contact between objects to be exerted. It acts only when two objects are in direct contact with each other

Question 25

what is non-contact force ?

Answer 25

A force that can act between objects even when they are not in direct physical contact

Question 26

what are some types of contact forces ?

Answer 26

- ground reaction force (GRF) - joint reaction force (JRF) - friction - fluid resistance - inertia force - muscle force - elastic force

Question 27

what are some types of non contact forces ?

Answer 27

gravity, magnetic and electrical

Question 28

TRUE OR FALSE ? forces usually act in pairs or in bodies ?

Answer 28

true

Question 29

what is net force ?

Answer 29

single resultant force derived from the vector composition of all acting forces

Question 30

TRUE OR FALSE? net force determines the net effect of all acting forces on a body

Answer 30

TRUE

Question 31

what are type of variables ?

Answer 31

scalars and vectors

Question 32

what is scalars ?

Answer 32

a quantity that is defined by its size/magnitude

Question 33

what are some examples of scalars ?

Answer 33

mass, energy, power, temperature, etc...

Question 34

what is vectors ?

Answer 34

a quantity that is defined by its size/magnitude AND direction

Question 35

how do we represent vectors ?

Answer 35

as arrows (length and pointing)

Question 36

what is length represented as ?

Answer 36

size/magnitude

Question 37

what is pointing represented as ?

Answer 37

direction

Question 38

what are some examples of vectors ?

Answer 38

force, moment, velocity, acceleration, etc.

Question 39

what is vector composition ?

Answer 39

the process of determining a single force (vector) from two or more forces (vectors) by vector addition (finding the resultant vector or net vector_

Question 40

what are the two types of vectors that steps depend upon ?

Answer 40

collinear and concurrent vectors

Question 41

what are colinear vectors ?

Answer 41

share the same line of action (parallel with each other

Question 42

what are concurrent vectors ?

Answer 42

do NOT share the same line of action

Question 43

TRUE OR FALSE colinear forces that have the same line of action can be same or opposite direction and tip to tail ?

Answer 43

TRUE

Question 44

how is the resultant found ?

Answer 44

by drawing an arrow from eh tail of the first force to the tip of the lat force

Question 45

FILL IN TH BLANK composition of vectors with _____ __________ requires adding their magnitudes

Answer 45

same direction

Question 46

what type of forces "do not act on the same line, but they do act through the same point" ?

Answer 46

concurrent forces

Question 47

what formula do we use to solve the missing side of a triangle ?

Answer 47

A² + B ² = C ²

Question 48

what is a vector ?

Answer 48

mathematical object that has both magnitude and direction

Question 49

what is force ?

Answer 49

is a push or pull that can cause an object to accelerate, decelerate or deform