Angular kinematics Flashcards
What is angular kinematics?
description of angular motion
what is angular position
orientation of a line relative to another line or a plane
what is absolute vs relative angular position?
in absolute the reference line/plane is fixed and in relative the line/plane is moveable
what is a radian ?/?
arc length/radius
how do u get degree to radians and radian to degrees
degree to radian = multiple by pi/180
radian to degree = multuply by 180/pi
what is angular displacement and what is the symbol?
angular displacement is the change in absolute angular position of a rotating line
the angle formed between the final and intial position of a rotaiting line
symbol = (Δθ)
is cw negative or positive?
negative
in angular motion do we consider distance travelled and sisplacemtnt he same?
yes
is angular diplacemtn the same for all points on a line?
yes
linear DISTANCE (arc length) travelled be a point on a line is ____ to distance from axis of rotation and angular displacemetn in _____
directly porprotional, radians
l = Δθr
How are linear displacement and linear distance different in terms of angular displacement?
linear distance is porpotional to angular displacement
linear displacement is NOT porportional to angular displacement
what is a chord? What is chord length also called?
line joining any 2 pts on a curve - chord length = lnear displacement
Why do we need large muscle force to produce small torque?
because muscles attach close to joint so have small moment arms and this os a mechanical disadvantage for torque production
what is a mechanical disadvanatge for torque production
muscles attach close to joints so there is a small moment arm so large muscle force is needed to produce small torque
Small movement near joint produces a large _____
linear displacement - mechanical advantage for lienar displacement
What is a mechanical advantage for linear displacement?
small movement near joint produces a large linear displacement - useful for sports equipment liike hockey sticks and rackets
State one mechanical advantage and disadvantage to
having muscle insertions close to the joint (axis of
rotation)
Adv - produces a great linear displacement from a small movement
disadv - requires a large msucle force to produce small torque due to small moment arm as msucle attaches very close to joint
What is angular velocity? Vector or scalar?
rate of change in angular displacement/ Vector
what is average w(ang v) important for? What is instantaneous ang v important for?
AVG: want to know how long it takes for something to rotate from A to B
– relevant to sports with twists/somersaults such as diving, gymnastics, figure skating
- same for all pts on a line
INSTANT: important if we want to know how fast smth is rotating at a given time.
- relevant to sports where a bat/stick/club strikes an object such as baseball, hockey, golf
what does s represent?
linear speed
what is VT
instantaneous tangential linear velocity
what is a tangent?
line which touches a circle at only
one point and is perpendicular to the radius
What s a mechanical advantage for linear velocity
Small movement near the
joint produced 8× greater
linear displacement at the
wris
- sports equipment as small movements
near axis of rotation produce large linear velocities
at business end of bat, stick, club, et
is angulat acc a vector or scalar?
vector
When does angular acceleration occur?
spins faster
spins slower
axis of spin changes direction
What are the 2 types of instantanepis linear acceleration assoc w angular motion?
tangential acceleration
centripetal acceleration
what is tangential acc?
isntantatneous lienar accelration at a tangent to the circular path
what is centripetal acceleration?
linear accelrations towards the axis of rotation
What is needed to maintain an object on a circular path?
centripetal - without it the object woudl travel at a tangent
Sprinters in lanes 1 and 4 have the same ____ velocity but a different ____ velocity
same tangential but different centripetal
if tangential velocity is kept constant what affect does this have on centripetal acceleration?
If tangential linear velocity is constant then centripetal accelration is inversely porpotional to radius - so a smaller radius means a greater centripetal acceleration
if angular velocity is kept constant what affect does this hav eon centripetal accelraton and radius
centripetal acc is porportional to radius so larger adius mean great centripetal accelration when angular velocity is constant
where is force and load on class one
