LECTURE #15 + 16 - angular kinematics Flashcards
what is angular motion ?
- rotation about a point
- within or outside body
what are the three units to measure angels ?
1) degrees
2) revolutions or rotations
3) radian
between degrees, revolutions/rotations and radians, which is the most common ?
degrees
between degrees, revolutions/rotations and radians, which is used for qualitative analysis ?
revolutions or rotations
between degrees, revolutions/rotations and radians, which is the most appropriate ?
radians
1 radian = how many degrees ?
57.3 degrees
what is a radian ?
ration of the arc length (r) of a circle to the radius length
what is the formula for radians (θ) ?
arc length / r
arc length & radius are units of length in what unit ?
meters
TRUE OR FALSE
radian is a dimensionless measure ?
TRUE
what are radians determined in multiples of ?
multiples of pi (3.14)
1 radian = ?
57.3 degrees
2 pi radians = ?
360 degrees
what is angular distance ?
- total of all angular changes during its path of motion
- analogous to linear distance
what is angular displacement ?
- difference between the initial and final position of a rotating object
- analogous to linear displacement
- indicate direction
what is angular speed ?
angular distance traveled per unit of time
what is angular velocity ?
- rate of change of angular displacement per unit of time
- direction depends on rotational direction
what is angular acceleration (alpha) ?
rate of change in angular velocity
what is an example of angular acceleration ?
throwing a baseball
what is the relationship between linear and angular motion ?
motion of any point go a rotating body can be explained in linear terms (d = displacement)
what do we need to know in the relationship between linear and angular motion ?
- axis of rotation
- radius f rotation (r) (distance from axis to point of rotation)
- kinematics in radians
TRUE OR FALSE
for linear distance and angular displacement d=θr
TRUE
what must θ be expressed in the units of for the expression to be valid ?
radians
TRUE OR FALSE
radians are “unit-less”
TRUE
if we see an increase in radius of rotation do we see an increase or decrease in linear displacement ?
increase
TRUE OR FALSE
linear velocity of rotating object is non tangential (perpendicular) to path of motion ?
FALSE
linear velocity of rotating object is TANGENTIAL (perpendicular) to path of motion ?
