Angular Kinematics Objectives• Distinguish angular motion from rectilinear and curvilinear motion• Review how segment and joint angles are measured • Discuss the relationship among angular displacement, angular

velocity, and angular acceleration• Correctly associate angular kinematic quantities with their units of

measure• Explain the relationship between angular and linear displacement,

angular and linear velocity, and angular and linear acceleration• Solve quantitative problems involving angular kinematic quantities

and the relationship between angular and linear motion quantities

Angular Kinematics Outline• Reading assignment: Chapter 11• Measuring angles

– Relative (joint) vs absolute (segment) angles– Measuring angles

• Goniometer (relative, or joint angles)• Inclinometer (absolute, or segment angles)• Electrogoniometer• Analytic calculation from 3 points in space

– Angular displacement– Units of measurement (degrees, radians, revolutions)

• Relationship between linear and angular motion• Linear and angular acceleration• Self-study problems:

– Introductory problems, pp 376-377: 4,5,7,10

• Homework problems (due Tuesday, April 11): – Additional problems, p 377-378: 1,10

Measuring joint & segment anglesJoint centers form Vertices for jt angles Joint angles Segment angles

Measuring angles of bodily segments

Leighton flexometer(absolute, or stegment angles)

Goniometer(relative, or joint angles)

Units of angular measurement

Degrees

Radians

Revolutions

Relationship between linear and angular motion (kinematics)

a = r

Relationship between linear and angular motion

• Would you rather have a long or short baseball bat or tennis racquet?

(sample problem 2, p 372)

Calculating linearVelocity whenAngular velocity & rotation radiusAre known

Tangential and radial acceleration

Tangential acceleration represents change in magnitude of velocity

Radial acceleration represents change in direction

Sample prob#3, p 375

Calculating tangential acceleration,Radial acceleration, and resultantacceleration