Sport Bio Test 3

Front 1

The rotary effect created by an applied force.

Back 1

Torque

Front 2

The angular equivalent of torque

Back 2

Linear Force

Front 3

Formula for torque

Back 3

T = Fd (product of the force and the force's moment arm)

Front 4

The shortest distance between the force's line of action and axis of rotation, also known as force or lever arm.

Back 4

Moment arm

Front 5

Why does a force that is directed through an axis of rotation produce no torque?

Back 5

Because the force's moment arm is zero

Front 6

When is it easiest to initiate rotation?

Back 6

When force is applied perpendicularly and as far away from the axis of rotation

Front 7

When is moment arm the largest?

Back 7

When the angle of pull on the bone is closest to 90 degrees.

Front 8

When net muscle torque and joint movement occur in the same direction.

Back 8

Concentric

Front 9

When net muscle torque and joint movement occur in the opposite direction

Back 9

Eccentric

Front 10

Factors that affect net joint torque.

Back 10

Weight and motion of body segments, action of external forces

Front 11

Positive and negative aspects of increased movement speed

Back 11

Positive - increased resultant joint torques during exercise, acceleration of load early in performance means involved muscles do not have to work as hard through the range of motion
Negative - during weight training can increase muscle tension and can lead to incorrect technique

Front 12

Agonist versus Antagonist

Back 12

Agonist means producing an action.
Antagonist acts in opposition to the movement generated by the agonist and is responsible for returning a limb to its initial position.

Front 13

Lever

Back 13

A simple machine consisting of a relatively rigid bar like body that can be made to rotate about an axis or fulcrum.

Front 14

First class lever

Back 14

F A R

Front 15

Second class lever

Back 15

A R F

Front 16

Third class lever

Back 16

A F R

Front 17

Example of levers in the human body

Back 17

The bone acts as the rigid bar, the joint as the axis, and the muscles apply the force

Front 18

Most of the lever systems formed by muscles pulling on bones are what class?

Back 18

Third

Front 19

The ratio of the moment arm of the force to the moment arm of the resistance for a given lever.

Back 19

Mechanical Advantage

Front 20

A motionless state in which there is no net force or net torque acting.

Back 20

Static equilibrium

Front 21

What conditions must be true for an object to be in a state of static equilibrium?

Back 21

Vertical force, horizontal force, and the sum of the torque acting on an object must all be zero.

Front 22

A concept that indicates a balance between applied forces and inertial forces for a body in motion.

Back 22

D'Alemberts principle

Front 23

The point around which a body's weight and mass are equally balanced in all directions, also referred to as the center of mass.

Back 23

Center of gravity

Front 24

Why is the center of gravity interest in the study of human biomechanics?

Back 24

It serves as an index of total body motion

Front 25

How can you find the center of mass for an object?

Back 25

By using a fulcrum to determine the location of balance.

Front 26

How can athletes use the center of gravity to their advantage in sports such as long jumping and pole vaulting?

Back 26

Lowering the center of gravity prior to takeoff enables athletes to lengthen the vertical path over which the body is accelerated during takeoff.

Front 27

Resistance to linear and angular acceleration or disruption of equilibrium

Back 27

Stability

Front 28

The ability to control equilibrium

Back 28

Balance

Front 29

Factors that can increase a body's stability/equilibrium

Back 29

Increasing body mass, increasing friction between the body and surfaces of contact, increasing the size of the base of support in the direction of an external force, horizontally positioning the center of gravity near the edge of the base of support on the side of the external force, vertically positioning the center of gravity as low as possible

Front 30

The area bound by the outermost regions of contact between a body and the support surface.

Back 30

Base of support

Front 31

Mechanisms that exert forces on bodies moving through them, may slow or propulse a moving body

Back 31

Fluid mechanisms

Front 32

A resistive force that slows the motion of a body moving through a fluid.

Back 32

Drag

Front 33

Factors of drag

Back 33

Coefficient of drag, fluid density, surface area of the body oriented perpendicular to the fluid flow, relative velocity of the body in respect to the fluid

Front 34

An index of the amount of drag an object can generate

Back 34

Coefficient of drag

Front 35

Factors that effect the coefficient of drag

Back 35

Shape (long bodies have lower coefficient of drag than irregular shaped objects), orientation of a body relative to fluid flow

Front 36

Example of how fluid density effects drag

Back 36

The thicker a fluid, the higher the force drag. An example would be having to produce more force to move an object through water than through air.

Front 37

The ______ surface area, the more drag force

Back 37

More

Front 38

The _____ the velocity, the higher the drag force

Back 38

Higher

Front 39

Occurs when a body moves through a fluid with enough velocity to create a pocket of turbulence behind the body and a pressure differential is created

Back 39

Form drag/pressure drag

Front 40

Generated perpendicular to fluid flow while drag forces act in the direction of free stream flow

Back 40

Lift force

Front 41

If the top of the object is curved during form lift, what occurs? What about if the object is flat?

Back 41

If curved, the air will accelerate and cause an area of low pressure. If flat, the object will remain at a low velocity which is associated with high pressure.

Front 42

A shape capable of generating lift in a fluid

Back 42

Foil

Front 43

The angle between the longitudinal axis of a body and the direction of fluid flow.

Back 43

Angle of attack

Front 44

For form lift to occur, a ________ angle of attack is necessary. What occurs if the angle of attack it too large?

Back 44

Positive; if the angle of attack is too large, the fluid cannot flow over the curved surface of the foil and no lift is generated.

Front 45

Occurs when an object in a fluid medium spins and the fluid molecules spinning with the object collide head on one side of the object and creates an area of high pressure.

Back 45

Spinning Lift

Front 46

Lift force created by spin

Back 46

Magnus Force

Front 47

An object will always move from an area of _________ pressure to _________ pressure. The object will move in the direction of _____ pressure.

Back 47

High to low. Moves in the direction of low pressure