216 lec14 general motion

Why do we use distance instead of displacement in angular kinematic

Distance moved around the circle is the actually distance travelled

measuring with displacement would underestimate how far the system moved

Linear translation = x

Radius of rotation x distance

We measure angular velocity in ___ when calculating general motion

Radians

Radius of rotation=

Distance btw axis of rotation and point of interest/contact

What’s tangent

The linear value of a point on a rotating rigid object at a distance from the axis of rotation represents the tangential quantity of that point

Tangential velocity vs linear velocity

Both solves for linear velocity, but tangential =linear movement that arise from angular movement

the linear change in position on a rotating object will be different at each point along the system, the further away from axis of rotation, the amount of change is dependent on ___

r (radius of rotation)

why do we use radian (instead of degree and revolution) for angular velocity

because radian is unitless/dimentionless. It is purely a ratio of the distance around the circle and its radius

how would choking up on a bat influence performance

decrease r, which decreases velocity

better control/precision

how would choking down on a bat influence performance

increase r, increase velocity

travel further (displacement), but less precision

before relating linear and angular variables, we need to ___

convert them into the same form

if a ball spin in a clockwise direction, which way will the ball linearly translate (L/R)

right

the tangent line ___ the rotating object but never__

touches

cross (parallel)