Kinesiology- Forces

true/false- the more work in time = less power?

false- more power

Negative ground reaction forces will do what?

increase impact to the body on landing

3 types of friction

static, sliding and rolling.

if there is too much stress, what happens?

there is permanent distortion

define- negative work

work done in the opposite direction the body is moving (eccentric exercises)

true/ false- force of 1 body is matched by and equal force in the same direction

false- force of 1 body is matched by an equal force in the opposite direction

true/ false- sliding friction has only a small area in contact with the ground

false- rolling friction

true/false- the lower the coefficient of elasticity, the lower the angle of rebound due to less distortion

false- the greater the angle of rebound

Law of reaction states

for every action, there is an equal and opposite reaction

Define- work

force applied against resistance over a particular distance

coefficient of elasticity is?

force divided by distortion

Define: summation of forces

force generated by muscles are added from 1 segment to another and causes it to move faster.

3 examples of composite forces

force of kick, force of gravity and force of wind

Define: concurrent forces

forces acting at the same point of application bue at different angles.

define- strain energy

form of stored energy, if object has the ability to rebound after distortion. (pole vault)

define- static friction

friction between 2 resting objects opposing initiation of motion

What happens to friction at low speeds as speed increases?

friction decreases

Magnitude must be what to move an object?

greater than the object's inertia

the relation of kinetic energy and momentum (3)

how much depends on mass and velocity, for every increase in velocity, the increase the work, if doubled mass = doubling the amount of kinetic energy

sprinters, speed skaters, and rowers use what to build momentum and acceleration?

impulse and cadence

Muscular force is?

in direct proportion to the number and size of muscle fibers. muscles usually act in a group and the point of application is where the muscles insert.

momentum can be changed by?

increase or decrease of object's mass, velocity or both.

with increased mass comes?

increased inertia

equation of inertia

inertia = mass + resistance to change in movement. mass = gravity (9.81).

3 forms of energy

kinetic, potential and strain

the names of newtons 3 laws are?

law of inertia, law of acceleration and law of reaction

3 types of composite forces

linear, concurrent, and parallel

Impulse of law of acceleration

longer time we apply force, the more the objects aceleration will increase. it is used to slow down to prevent injury

3 qualities of forces

magnitude, direction, and point of application

define- kinetic energy

mass on the move

Define- point of application

point at which force is being applied

Define- momentum

product of mass x velocity

Positive ground reaction forces will do what?

propel forward, into the air, etc.

define- sliding friction

resistive force between 2 objects that are sliding/ rubbing eachother

define- rolling friction

resistive force between a round object that is rolling over a surface

define potential energy

stored energy. ready to put to work due to its position.

5 types of elasticity

tension, compression, bending, tortion, and shearing

Law of inertia states?

that the body continues in a state of rest of motion unless acted upon by another unbalanced force

define- elasticity

the ability to resist distortion and return to regular size adn shape.

Action line is also known as?

the line of pull

with spinning balls on vert. surfaces, the ball will have?

the same speed with horizontal. speed

the amount of recoil depends on?

the type of surface it comes in contact with

Factors of force will determine what?

the type of which motion will occur.

the more stress applied causes what to happen with distortion?

to increase

the 4 effects of spin on the ball?

top spin, back spin, no spin, spinning balls with vertical surfaces.

examples of concurrent forces

triceps, gastroc and soleus, deltoid, steering wheel

t/f- anything above or off the ground is potential energy?

true

t/f- the more mass and faster moving the increased kinetic energy and momentum

true

true/ false- due to the factors, there are rules that limit each rolling friction factor?

true

true/ false- force applied in direction of motion will increase momentum and vise versa?

true

true/ false- static friction is the worst kind of friction

true

true/ false- the more friction between objects, the lower the angle of rebound

true

true/false- with no sping, hte ball will develop top spin if there is any angle of contact?

true

Tortion is a?

twisting force ( twist apple)

Rolling friction depends on what 3 things?

type of surfaces in contact, amount of pressure pushing them together, and the diameter of rolling object

What is a force that modify motion?

weight (force of gravity on mass)

magnitudes formula

weight = mass x gravitational pull

Linear force is..?

when it is applied in the same direction along the same action line, or vise versa.

tension is?

when stretch is applied and it returns to normal

define-positive work

work done in the same direction the body is moving (biceps curl)

true/ false you must overcome sliding friction to gain motion?

false, static friction

Define- composite forces

2 or more forces acting on an object.

Friction is between?

2 solid surfaces

Define- parallel forces

Forces that do not have the same action line, but act parallel to eachother.

true/ false- muscles work separately from one another

false, muscles work in groups, they are known as the composite muscles of the body

If you are on different parts of the earth what will happen and why?

You can be heavier or lighter. heavier if you are closer to the center of the earth due to increased pull

shearing is?

a rubbing force (abrasion when falling to ground)

Law of acceleration states?

acceleration of an object is directly proportional to the force causing it, in the same direction of that force, and it's inversly proportional to its mass.

any change in momentum is what to the impulse that produced it?

equal

Newton's law of Gravitations states..?

all ovjects are attracted to eachother in direct proportion to mass and inversly proportional to the distance between them (the larger and close together the objects are the more attracted they are)

Define- power

amount of work done in a particular time

Angle of rebound depends on what? (5)

angle of velocity of contact, if ball was spinning at the angle of contact, coefficient of elasticity, how much friction is present and the temperature of the object (if temp is increased, rebound increases)

Define- conservation of momentum

any forces that act on eachother, the momentum is constant.

with top spin, a rebound is?

at a lower angle with higher horizontal speed

with back spin, the rebound is?

at higher angle with decreased horizontal speed

bending is?

bending an object (paper clip)

Components of parallel forces (5)

can act in the same and different directions, if forces are balances it means no motion, if forces are unbalance it means rotation motion, if 2 parallel forces opposite to eachother is means rotation and if 2 parallel forces are equal and same direction it means they r linear

define- energy

capacity of a person or object to do work

No motion does what to work?

causes no work

at high speeds, there is a proportional increase in friction causing what?

causing the generation of heat and disinigrating the object

Define- anatomic pulley

change the angle of pull of a muscle so we increase the rotary component and improve mechanical advantage

what is due to teh direction, and point at which force is being applied?

composite forces

compression is?

compressing an object, like a stress ball.

examples of things that limit rolling friction factors

dimples on a golf ball (aids in flight), bike tires (narrow for speed or wide for friction)

the closer the force is applied in direction of desired motion, the more fluid motion will be is considered what?

direction of force

coefficient of elasticity equation is

e= square root of bounce height divided by drop height. the closer to 1 is the more elastic

Things rebound in a predictable manner depending on what 5 things?

elasticity, mass, velocity of rebounding surface, friction between surfaces, and angle of contact

define- conservation

energy changing between forms