Linear Kinetics

Question 1

Force definition

Answer 1

Mechanical action or effect applied to a body that tends to produce acceleration

Question 2

What is the unit of force? How do these units compare to pounds?

Answer 2

Newtons
1 lb = 4.448 N

Question 3

What is the purpose of a free body diagram (FBD)

Answer 3

Simple diagram of an isolated object of interest designed to understand the externally applied forces on an object

Question 4

What must be followed when making a FBD?

Answer 4

Newton’s laws

Question 5

What is the first law of motion?

Answer 5

Law of inertia

Question 6

What is the second law of motion?

Answer 6

Law of acceleration

Question 7

What is the third law of motion?

Answer 7

Law of action reaction

Question 8

What is the law of inertia?

Answer 8

An object in motion stays in motion unless acted upon by an outside force

Question 9

Inertia

Answer 9

Resistance of a body to change its state of motion/keeping something in a constant state

Question 10

What is uniform motion?

Answer 10

Constant momentum (m)(v)

Question 11

What is the law of acceleration?

Answer 11

F=ma

when m is constant

An object’s change of motion is proportional to the force acted on it in the direction of the straight line where the force is impressed

Question 12

What is acceleration referring to?

Answer 12

Of the object’s center of mass (COM)

Question 13

What is the linear equation of motion (EOM)

Answer 13

F=ma

Question 14

What is the inertial force known as in the EOM

Answer 14

ma

Question 15

Statics

Answer 15

Branch of mechanics where a system undergoes no acceleration

(Velocity is constant)

Question 16

Dynamics

Answer 16

Branch of mechanics where a system undergoes an acceleration

(Velocity is not constant)

Question 17

True or false:

A static object means it always has no velocity

Answer 17

False

Static means constant velocity so it is still moving, just with no acceleration

Question 18

Match static, dynamic, equilibrium, and not in equlibrium

Answer 18

Static- in equilibrium
Dynamic- not in equilibrium

Question 19

True or false:

Static mechanics only cares about kinetics

Answer 19

False:

Cares about kinematics too since it can still have a velocity

Question 20

What is the law of action reaction?

Answer 20

For every action there is an equal and opposite reaction

Question 21

True or false:

Forces cancel out in Newtons 3rd law

Answer 21

False

One force acts on one object and the other on another object

Question 22

What is the law of universal gravitation?

Answer 22

All objects attract each other with a gravitational force inversely proportional to the square distance between objects

Question 23

What does the force of gravity depend on the proportionality of?

Answer 23

Masses of the two bodies being attracted to each other

Question 24

Mass (m)

Answer 24

How much matter is in an object

Scalar

Question 25

Weight (W)

Answer 25

Force due to gravitational acceleration *Vector*

Question 26

True or false Body weight (N) = Body mass (kg)

Answer 26

False These are not interchangeable

Question 27

Center of mass (COM)

Answer 27

The point in which all the particles of the body are evenly distributed *Always exists*

Question 28

Center of Gravity

Answer 28

Point in which weight due to gravity acts on a body *Exists when gravity exists*

Question 29

Ground reaction force *Distributing force*

Answer 29

Term that includes the normal and tangential (friction) force

Question 30

Center of pressure

Answer 30

Singular point of application of the ground reaction force (GRF)

Question 31

Which type of forces are we more concerned with?

Answer 31

External forces

Question 32

True or false: Muscle forces would be considered internal forces

Answer 32

True

Question 33

What three things at a joint can alter the COM motion of a body segment?

Answer 33

Muscles Ligament Bone on bone forces

Question 34

Kinematics

Answer 34

Area of study that examines the spatial and temporal components of motion Position, velocity, acceleration, etc...

Question 35

Kinetics

Answer 35

Study of the causes of motion Forces, torque, impulse, momentum, work, power, energy

Question 36

True or false: Kinetics is the study of both motion and the causes for motion

Answer 36

False Only the causes for motion

Question 37

Is force a vector or scalar?

Answer 37

Vector- includes magnitude and direction

Question 38

Is gravity an internal or external force?

Answer 38

External (affects the COM)

Question 39

Does the force of gravity change depending on where you are on Earth?

Answer 39

Yes- elevation affects gravity

Question 40

The property of an object to resist motion

Answer 40

Inertia

Question 41

The law of inertia describes _______ conditions with the sum of the external forces equal to zero

Answer 41

Static

Question 42

When does linear momentum only need to stay constant?

Answer 42

When the external forces sum to zero

Question 43

In order to use EOM, what must remain constant with time?

Answer 43

Mass

Question 44

External forces causes changes in the _____ while internal forces may alter the object's _____

Answer 44

COM Shape

Question 45

Muscles would be an example of what type of force?

Answer 45

Internal

Question 46

How would you find the direction of acceleration from vectors?

Answer 46

Split into x and y components and determine the greater magnitude and direction