Biomechanics Final Exam(s) Review

linear velocity

(v)

2.2 lbs=

1 kg

4.448 N

1 lb

Newton's Second Law

The Law of Acceleration

Adolescence

The complete ossification of long bones generally occurs by the end of __________________.

Friction

The component of the contact force that acts parallel to the surfaces in contact. It opposes the motion of an object.

Force Arm

The distance between the Axis and the Force is known as the __________

Resistance Arm

The distance between the axis and the resistance is known as the_________

Acceleration

velocity ---------- elapsed time

Weight

The measure of the force of gravity acting on an object

True (2)

The muscle spindle is responsible for the "stretch reflex"

Moment Arm (r) muscle force

The perpendicular distance from the muscle's line of force and the axis of rotation

Angular Displacement

△θ = final position (θ) - initial position (θ)

A cyclist is going down a steep hill when a stick gets lodged in his wheel. Which of the following is true?

The stick applied a torque that was the opposite direction of the wheel rotation

Performing elbow flexion using the biceps brachii with a weight in your hand is an example of a _______ class lever

Third

Angular kinematics 5 variables

Time Position Displacement Velocity Acceleration

Type 1 Muscle Fibers

Used for low force/speed activities that last > a few minutes.

have increased O2 metabolism

When I endurance train my muscles, they will __________________.

Principle Axes

When an object is not symmetrical, it can rotate around multiple axes.

Solve vertical equations then horizontal equations

Which represents the correct order to solve a projectile motion problem?

Shear

Which type of stress is considered a transverse stress?

Negative (-)

clockwise

Linear momentum/moment of inertia

is a vector and is measured in kg-m-s2.

Kinetics

the branch of dynamics concerned with the forces that cause or tend to cause motion

Length

the space in which movement occurs

Average linear acceleration

αavg = △ω / △t

Wolff's Law

"The strength of bones will increase according to the lines of physical stress placed upon them." What is the name of the above rule?

angular velocity

(w)

A figure skater's second spin begins with an angular velocity of +300 degrees/s. From that point until their 5th spin is .99 seconds. If the start of the 5th spin is measured at +1400 degrees/s, what is their average angular acceleration

+1,111 degrees per second squared

This person is doing a deltoid raise. If she starts with her arms at her side, and abducts her shoulder through 120 degrees range of motion, and the action takes 4 seconds, what is her average angular velocity.

+30

This person is doing a triceps extension. If she extends her elbow through 90 degree range of motion, and the action takes .25 seconds, what is her average angular velocity?

+360 degrees/s

This person is doing a biceps curl. If their elbow moves from the position below (90 degrees) to full flexion (160 degrees), what is the angular displacement?

+70 degrees

The person is doing a shoulder flexion exercise. If their shoulder moves from a relaxed position (0 degrees) to the position below (90 degrees shoulder flexion), what is the angular displacement?

+90 degrees

A weightlifter is attempting a biceps curl with a 400 N barbell. The moment arm of the barbell about the elbow joint is 40 cm. What torque is created by the barbell around the elbow joint?

-160Nm

The person is doing a hip extension exercise. If their hip moves from the floor (90 degree hip flexion) to the position below (45 degree hip extension), what is the angular displacement? Assume the positions between flexion and extension is 0 degrees. Analyze with the assumption that the person is facing right.

-45 degrees

The person is doing a hip extension exercise. If their hip moves from the floor (45 degree hip flexion) to the position below (45 degree hip extension), what is the angular displacement? Assume the positions between flexion and extension is 0 degrees. Analyze with the assumption that the person is facing right.

-90 degrees

You are doing a deltoid/shoulder raise from a standing position. The weight is 30 lbs (133N) and the distance from your elbow to the weight is 40 cm. What is the total torque produced by the weight if your shoulder is in neutral/you are holding it straight down?

0 Nm

The person is spinning around as she prepares to do a hammer throw. If her entire body completes exactly 3 spins, and all three spins together take .95 seconds, what is her body's average angular velocity?

1,137 degrees/s

This hammer thrower begins their spin with an angular velocity of 0. If the hammer thrower reaches an angular velocity of +1100 degrees/s in .8 seconds before releasing the hammer, what was her body's average angular acceleration?

1,375 degrees per second squared

A person is running on a windy day. If the person is running at 6 m/s and the wind is hitting them directly in the back at 2 m/s, what is the relative velocity?

8 m/s

Female's

A _________ center of gravity is slightly lower than a male's center of gravity

Newton's First Law (Law of Inertia)

A body at rest or in uniform linear motion, will tend to remain at rest or in uniform linear motion, unless acted upon by an external force.

Sesamoid Bone

A bone completely encased in connective tissue such as tendon or ligament (e.g patella)

General Motion

A change in position that results from a combination of linear and angular motion

Newton's Second Law (Law of Acceleration)

A force acting on a body will produce an acceleration proportional to the force. F = mass x acceleration

Newton's Second Law - Restated for Angular Motion

A net external torque acting on an object will produce a change in angular momentum that is proportional to the net external torque exerted on it. (The change will be in the direction of the net external torque.)

Fiber

A single muscle cell

Proprioception

A subconscious mechanism by which body is able to control posture and movement by responding to stimuli originating in proprioceptors of the joints, tendons, muscles, and inner ear.

Elastic

Able to return from a deformed shape to the original dimensions when the stress causing the deformation is removed.

Superior

Above in relation to another structure; higher, cephalic

For a body to be in static equilibrium ______________.

All of the answers are correct

Eccentric Axis

An axis that is not through an object's center of gravity is called an eccentric axis.

Projectile

An object that has no external forces acting on it other than the force of gravity

Rate of change of angular velocity; expressed in units of angular displacement divide by time squared or expressed in radians per second per second or revolutions per second per second; a vector quantity.

Angular Acceleration

Change in absolute angular position experienced by a rotating line with the direction of the change indicated; the angle between a line segment in its initial position and in its final position with the direction of rotation noted; measured as units of angular position or expressed as radians, degrees or revolutions

Angular Displacement

Average torque times the duration of application of the torque; causes and thus is equal to change in angular momentum; measured in units of torque times units of time or expressed as newton-meter-seconds in SI; a vector quantity.

Angular Impulse

Average torque times the duration of application of torque; causes and thus is equal to change in angular momentum; measured in units of torque times units of time or expressed as newton-meter-seconds in SI; a vector quantity.

Angular Impulse

Property of an objects to resist changes in its angular motion

Angular Inertia

Moment of inertia times angular velocity; measured in units of mass times units of velocity or expressed as kilogram-meters squared per second in SI; a vector quantity

Angular Momentum

moment of inertia times angular velocity; measured in units of mass times units of velocity or expressed as kilogram-meters squared per second in SI; a vector quantity.

Angular Momentum

Orientation of a line relative to some other line or plane; expressed in degrees or radians

Angular Position

Dorsiflexion Examples

Ankle Dorsiflexion Toe Dorsiflexion

Eversion examples

Ankle Eversion

Plantar Flexion Examples

Ankle Plantar flexion Toe Plantar flexion

Inversion examples

Ankle inversion

The length of a force arm or a resistance arm is determined by the distance of the force or resistance from the ______.

Axis

1st class lever

Axis (A) between force (F) & Resistance (R)

A F R

Axis Force Resistance

A R F

Axis Resistance Force

A cliff diver jumps and starts spinning around. What type of axis of rotation will the cliff diver have?

Axis will be at center of gravity

A skydiver jumps out of a plane and starts spinning around. What type of axis of rotation will the skydiver have?

Axis will be at center of gravity ****

Upward force acting on an object in fluid that is equal to the weight of the fluid displaced

Buoyancy

A water polo player shoves the ball under the water. It pops back up into the air above. What best explains why this happens?

Buoyant Force

Bending Stress

Causes a compression side and tension side A tension side fracture takes a lot longer to heal because the healing part of the bone is always being pulled apart. A compression side fracture is still serious but will heal quicker because the broken pieces are approximated.

The area beneath and between the points of contact an object has with the ground is called:

Center of gravity

An external force directed through the center of gravity

Centric Force

This cowboy must pull the rope towards himself in order to cause rotation of the lasso. Once he lets go, the lasso will fly off in a straight line. The pulling action is due to _______ acceleration whereas the flying action is due to ______ acceleration.

Centripetal / tangential

This male figure skater must pull the female skater towards him in order to cause her to rotate around him. If their hands slip, and he lets go, she will fly off in a straight line. The pulling action is due to ________ acceleration whereas the flying action is due to ______ acceleration.

Centripetal / tangential

Linear acceleration of a point on a rotating object measured in the direction perpendicular to the circular path of the object (along a line through the axis of rotation or along a radial line); measured in units of length divided by units of time squared or expressed as meters per second per second in SI; a vector quantity

Centripetal Acceleration

Which two properties are the primary determinants for an object's moment of inertia?

Distribution of mass relative to the center of gravity Mass

Starting from anatomical position, the ankle joint action that occurs around a transverse axis and causes the foot to move in a sagittal plane such that it move downward and away form the leg

Dorsiflexion

Force that acts on an object in opposition to the motion of the object

Drag

An axis that does not pass through the implement's center of gravity

Eccentric Axis

Starting from anatomical position, the joint action that occurs around an anterior-posterior axis through the ankle when the lateral side of the sole of the foot is lifted

Eversion

If the distribution of mass becomes ______ the center of gravity, the moment of inertia will increase.

Farther away from

Impulse

Force x duration of force application causes a change in momentum.

Drag force caused by the impact forces of the fluid molecules with the object based on the object's shape.

Form Drag

Opposite

Friction always acts _____________ the direction of movement (actual or impending movement).

Starting from a position of the hip or shoulder abduction, the shoulder or hip joint action that causes movement of the arm or leg in the transverse plane around a longitudinal axis such that the arm or thigh moves back toward the midline of the body

Horizontal Adduction

angular momentum equation

Hα = Iαωα H= angular momentum (axis α) I = moment of inertia (axis α) ω=angular velocity (axis α)

moment of inertia (I)

I = mr2

Axis at center gravity

If an object is free (not constrained) to rotate around any axis, it will rotate around the axis that is through the center of gravity.

2

In a projectile motion problem, if the projectile is a parabola, you can multiply the time by _____ to get the total time in the air.

Starting from anatomical position, the joint action that occurs around an anterior-posterior axis through the ankle when the medial side of the sole of the foot is lifted.

Inversion

The branch of dynamics concerned with the description of motion (as apposed to the forces causing the motion)

Kinematics

A person is running on a windy day. If the person is running at 5 m/s and the wind is hitting them directly in the back at 1 m/s, what is the relative velocity?

4 m/s

Curvilinear Motion

Linear motion that occurs when an object maintains its orientation during a movement so that all points on the object move the same distance, in the same direction and in the same time, but NOT in straight lines

A discus thrower spins around in a circle three times before releasing the discus. What principal axis will the discus thrower have and what plan is the spin in?

Longitudinal axis / sagittal plane

Stability may be increased by __________

Lowering the center of gravity with a wider base of support

Measure of angular inertia; sum of the product of the mass of each part of an object and the square of the distance each part is from the center of gravity of the object; mass times radius of gyration squared; measured in units of mass times units of length squared or expressed as kilogram-meters squared in SI; a scalar quantity

Moment of Inertia

Lateral flexion

Movement of the trunk or neck to the left or right in a frontal plane around an anterior-posterior axis.

Flexion Extension Dorsiflexion Plantar Flexion

Movements that act in a sagittal plane and through a transverse axis

Internal rotation External rotation Rotation Pronation Supination Horizontal Abduction Horizontal adduction

Movements that act in a transverse plane and through a longitudinal axis

Lateral flexion Abduction Adduction Radial Deviation Ulnar Deviation Inversion Eversion

Movements that in a frontal plane and through an anterior-posterior axis

Concentric Contraction

My athlete is hanging from a chin up bar and pulling himself up very quickly. What type of contraction is this?

Extension Example

Neck Extension Shoulder Extension Elbow Extension Wrist Extension Finger Extension Trunk Extension Hip Extension Knee Extension

Flexion Examples

Neck Flexion Shoulder Flexion Elbow Flexion Wrist Flexion Finger Flexion Trunk Flexion Hip Flexion Knee Flexion

Lateral flexion examples

Neck lateral Flexion (R or L) Trunk Lateral Flexion (R or L)

Rotation examples

Neck rotation (R and L) Trunk Rotation (R and L)

Force (F)

Point of force application (usually at the muscle insertion)

Resistance (R)

Point of resistance application (center of gravity including the weight of the body segment and/or an external weight)

An external force and the area over which this force acts

Pressure

What is true about buoyant force?

Pressure is the same on all sides

Axis about which an object's moment of inertia is the largest; axis about which an object's moment of inertia is the smallest; axis perpendicular to the two previously defined principal axes.

Principal Axis

Poisson's Ratio

Ratio between transverse strain and strain in the axial direction for a object loaded axially

Cyclists often crouch on their handlebars during a race. Why do they race crouching down instead of sitting up?

Reduce form drag

Luge athletes lay down and point their toes in while racing quickly down the hill. Why do they race laying down instead of sitting up?

Reduce form frag

A swimmer shaver all his body hair before a race. What is he trying to do?

Reduce surface drag

Angular Motion

Rotary motion or rotation; occurs when all on a body or object move in circles (or parts of circles) about the same fixed central line or axis

Performing a standing heel raise is an example of a ________ class lever

Second

Hyaline Cartilage

Shiny, white, smooth cartilage that makes up the articular cartilage covering the articular surfaces of bones in synovial joints.

Adduction examples

Shoulder Adduction Hip Adduction

External Rotation examples

Shoulder External Rotation Hip External Rotation

Internal Rotation examples

Shoulder Internal rotation Hip Internal rotation

External Rotation

Shoulder or hip joint actions that occur around longitudinal axes through these joints and cause limb movements in the transverse plane such that the knees turn away from each other or the palms of the hands turn away from the body; the opposite of internal rotation; also referred to as lateral rotation or outward rotation.

Lateral Axis

Sit Up

Articular Capsule

Sleeve of ligamentous connective tissue surrounding a synovial joint

The ability of an object to return to its original position after it has been displaced is called:

Stability

Horizontal Adduction

Starting from a position of hip or shoulder abduction, the shoulder or hip joint action that causes movement of the arm or leg in the transverse plane around a longitudinal axis such that the arm or thigh moves back toward the midline of the body; the opposite of horizontal abduction. EX) Shoulder Horizontal Adduction Hip Horizontal Adduction

Horizontal Abduction

Starting from a position of hip or shoulder flexion, the shoulder or hip joint action that causes movement of the arm or thigh in the transverse plane around a longitudinal axis such that the arm or leg moves away from the midline of the body; the opposite of horizontal adduction. EX) Shoulder Horizontal Abduction Hip Horizontal Abduction

Pronation

Starting from anatomical position the radioulnar joint action that occurs around the longitudinal axis of the forearm and causes the palm to turn toward the body; the opposite of supination. EX) Forearm Pronation

Internal Rotation

Starting from anatomical position, shoulder or hip joint actions that occur around longitudinal axes through these joints and cause limb movements in the transverse plane such that the knees turn inward toward each other or the palms of the hands turn toward the body; the opposite of external rotation; also referred to as medial rotation or inward rotation.

Plantar Flexion

Starting from anatomical position, the ankle joint action that occurs around a transverse axis and causes the foot to move in a sagittal plane such that it moved downward and away from the leg; the opposite of dorsiflexion.

Dorsiflexion

Starting from anatomical position, the ankle joint action that occurs around a transverse axis and causes the foot to move in a sagittal plane such that it moved forward and upward toward the leg; the opposite of plantar flexion.

Flexion

Starting from anatomical position, the joint action that occurs around a transverse axis through a joint and causes limb movement in a sagittal plane away from anatomical position through the largest range of motion; the opposite of extension.

Abduction

Starting from anatomical position, the joint action that occurs around an anterior-posterior axis through a joint and causes limb movements in a frontal plane through the largest range of motion. The opposite of adduction.

Eversion

Starting from anatomical position, the joint action that occurs around an anterior-posterior axis through the ankle when the lateral side of the sole of the foot is lifted; the opposite of inversion.

Inversion

Starting from anatomical position, the joint action that occurs around an anterior-posterior axis through the ankle when the medial side of the sole of the foot is lifted; the opposite of eversion.

Tensile

State of an object as a result of forces pulling on it; axial stress that tends to pull molecules apart and stretch the object.

Compression

State of an object as a result of forces pushing on that are producing axial stress that tends to push molecules together and squash an object

Failure Strain

Strain at which a material breaks or fails

Yield Strength

Stress above which plastic deformation will occur.

Drag force caused by friction between the fluid and the surface of the object

Surface Drag

I am trying to determine how much force a hamstring must create when doing an isometric hamstring curl of a given weight. If I know (because I can measure) the moment arm for both the hamstring and the weight, which equation is most appropriate?

T1 = -T2

Newton's First Law

The Law of Inertia

amount of force; proportional

The _____ that can be exerted by a muscle is ________ to the moment arm.

Torque (moment of force)

The ability of a force to produce rotation around an axis

Most people are able to float if they rake a large breathe of air. What best explains why?

The air in the lungs make the body less dense

True (1)

The amount of strength generated will depend on the number of motor units that are activated as well as frequency of stimulation. (1)

amount of force; perpendicular

The amount of torque a lever has depends on the ______________ exerted and the __________ distance from the line of force to the axis

proportional

The amount of torque that can be generated by a muscle is ________ to the moment arm.

Newton's First Law - Restated for Angular Motion

The angular momentum of an object remains constant unless a net external torque is exerted on it.

An aerialist for Cirque de Soleil is spinning on two long ropes. She pulls her arms and legs tight to her body. Which of the following will increase?

The angular velocity The moment of inertia

A badminton player hits the shuttlecock with her racquet. What type of axis of rotation will the racquet have?

The axis will be eccentric

What happens to your center of gravity when you add a 200 N suitcase to your hand held out to your side?

The center of gravity shifts in the direction of the suitcase

A gymnastics coach is assisting a gymnast who is doing a giant swing around the bar. If the coach desires to increase the angular impulse, which of the following actions will work?

The coach could push harder (in the same direction as the rotation) The coach could increase the time of the push (in the same direction as the rotation)

Contractility

The hamstring muscle is able to generate force against resistance when stimulated. This occurs because muscle has which property?

Extension

The joint action that occurs around a transverse axis through a joint and causes limb movement in a sagittal plane back toward anatomical position; the opposite of flexion.

Adduction

The joint action that occurs around an anterior-posterior axis through a joint and causes limb movements in a frontal plane back toward anatomical position. The opposite of abduction.

Ulnar Deviation

The joint action that occurs around an anterior-posterior axis through the wrist joint and causes movement of the hand in a frontal plane in the direction of the little finger ; the opposite of radial deviation; also referred to as adduction or ulnar flexion.

Radial Deviation

The joint action that occurs around an anterior-posterior axis through the wrist joint and causes movement of the hand in a frontal plane in the direction of the thumb; the opposite of ulnar deviation; also referred to as abduction or radial flexion.

Newton's Third Law

The law of Action-Reaction

During angular motion, what is the relationship between the length of the moment arm and the torque created (when the force used in constant)?

The longer the moment arm, the greater the torque

A baseball player chooses a bat that is longer. How will the moment of inertia compare to a shorter bat?

The moment of inertia will be greater

A tennis player chooses a racquet that is shorter. How will the moment of inertia compare to a longer bat?

The moment of inertia will be smaller

Center of Mass/Gravity

The point at which the entire weight of the body may be assumed to be concentrated

Inertia

The property of an object to resist changes in its motion.

Supination

The radioulnar joint action that occurs around the longitudinal axis of the forearm and returns the forearm and hand to anatomical position after being pronated or moves them beyond anatomical position; the opposite of pronation. EX) Forearm supination

Linear acceleration (α)

The time rate measurement of change in velocity Measured in degrees per second per second

Johnathan us doing a seated knee extension exercise. If we know that the quadriceps is creating 8,000N of torque in the counterclockwise direction, what do we know about the torque of the weight that he is lifting if we assume the system is in equilibrium?

The torque of the weight is -8,000N

Angular impulse

Torque x duration of torque application causes a change in angular momentum.

A gymnast performs a backwards roll (backwards somersault). Which principal axis will this activity have and what plane is the backward roll in?

Transverse axis / sagittal plane

Rotation

Turning around an axis or center point.

Type 2B Muscle Fibers

Used for high force/speed activities that last < a minute

Type 2A Muscle Fibers

Used for hybrid activities that last 1-3 minutes

I am trying to determine how much torque a weight will create while doing a triceps extension. What must I know in order to determine the torque?

Weight (N) and moment arm (m)

Osteoblast

What type of cell creates bone?

Inversely proportional

When doing a concentric contraction, the force and velocity are ____________.

Proportional

When doing an eccentric contraction, the fore and velocity are __________.

Osteoarthritits

Which condition results as people age or if they have a past traumatic injury to a bone or joint?

Radial Deviation examples

Wrist radial deviation Fingers radial deviation

Ulnar Deviation examples

Wrist ulnar deviation Fingers ulnar deviation

Stability

Your center of gravity is related to _______

Strain

_____ is the deformation

Stress

______ is the force/load applied

Failure Strength

_______ is the stress when it breaks or fails

Third class levers

_________ are the most common type of lever in the body

infants and children

____________ and ________ have higher centers of gravity because of their relatively larger heads and shorter legs

The moment arm of the biceps brachii muscle about the elbow joint is largest when the angle at the elbow joint is approximately _________.

90 Degree

Positive (+)

counterclockwise

Velocity

displacement ----------------- change in time

Speed

distance traveled -------------------- time elapsed

3rd class lever

force (F) between axis (A) & resistance (R)

A weighted object

force will always be downward because gravity always acts downward

Actual force (F) muscle force

generated by the muscle

Synovial joint

A ball-and-socket joint is classified as a ________________.

Torsion

A load that causes an object to twist due to torque; torques in opposite directions acting on either end and around the longitudinal axis of an object produces shear stresses in the analysis plan that become larger with increased distance from the longitudinal axis; as a result of a torsion load, an object will deform by twisting.

Center of Mass

A point that represents the average location of a system's mass

Motor Unit

A single motor neuron & all muscle fibers it innervates (all muscle fibers are same type).

What is torque?

A turning effect produced by a force

-9.81 m/s2

Acceleration due to gravity

Scapula

An example of a flat bone is _________________.

Plane of Motion

An imaginary two-dimensional surface through which a limb or body segment is moved

static equilibrium

An object is at rest

Actual force (F) resistance

is caused by weight of resistance

Which is true about buoyant force?

it is always vertical It is caused by pressure

Diffusion

Cartilage does not have a blood supply, so it relies on __________ to get nutrients.

momentum (p) equation

mass x velocity

Structure of Skeletal muscle

myofilament; myofibril; muscle fiber/cell; fascicle; endomysium; perimysium; epimysium; tendon/apo

The ratio of the mass of an object to the volume of fluid in which it is immersed

Density

The joint action that occurs around a transverse axis through a joint and causes limb movement in a sagittal plane back toward anatomical position

Extension

Newton's Third Law (The Law of Action-Reaction)

For every action, there is an equal and opposite reaction.

Nm

Force (N) x moment arm (m)

F A R

Force Axis Resistance

Parallel

Friction always acts _____ to the contacting surfaces

Axis (A)

Fulcrum; The point of rotation

2nd class lever

resistance (R) between axis (A) & force (F)

T = (F)(r)

resistance/muscle torque is calculated using _______-

False (1)

Half of the fibers in a motor unit will contract if the stimulus is half as much.

Greater; Harder

If the axis is located closer to the force, then the resistance arm will be ___________ and it will be _____ to move the resistance

Equal

If the axis is located directly in the center between the force and the resistance, the force arm and resistance arm length will be _______

Greater; Easier

If the axis located closer to the resistance, then the force will be _______ and it will be _________ to move the resistance

Resting length

In which position will a muscle be the most able to generate force?

What is the purpose of the blue attachment on the helmet above?

Increase laminar flow

A baseball pitcher is able to throw a pitch that changes direction mid-flight. How is that possible?

Magnus Effect

Creep

Material behavior characterized by a continued increase in strain under a constant stress.

Angular velocity

Measured in degrees per second

Newton's Third Law - Restated for Angular Motion

Newton's Third Law - Restated for Angular Motion

The drag force is always ______________.

Perpendicular to the fluid flow

Cancellous Bone

Porous, less dense bone tissue found deep to cortical bone near the ends of long bones; also referred to as spongy or trabecular bone.

Starting from anatomical position the radioulnar joint action that occurs around the longitudinal axis of the forearm and causes the palm to turn toward the body

Pronation

Abduction examples

Shoulder Abduction Hip Abduction

Frontal Plane

Side bend

Moment arm (r)

the perpendicular distance from the resistance line of force and the axis of rotation

Center of Gravity

the point in a body or system around which its mass or weight is evenly distributed or balanced and through which the force of gravity acts

Angular Momentum

the product of an object's moment of inertia and its angular velocity. will be greater if the object has either a greater moment of inertia, or more angular velocity (or both).