BIOMECHANICS APPLICATIONS

1
For Lab 3 Review Slides SS16 for Next Lecture

• Throw Open Kinetic Link
• proximal segments in front, distal segments
  behind projectile
• sequential for ? v
• curvilinear path
• mostly wheel-axle

• Push Closed Kinetic Link
• all segments behind projectile pushing the
  projectile or load
• simultaneous for ? F
• rectilinear path
• mostly lever motions

2
L Angular Momentum

• L I ?
• ? is angular velocity
• I is rotational inertia - a bodys resistance to
  change angular motion
• I mk²mass x distance² that the mass is away
  from axis of rotation

3
Tt Angular Impulse

• Tt Torque x time of Torque application
• Tt ? L (i.e. I?-2 minus I?-1)
• see Figure I.2 on page 328

4

• T F x FA
• F is board reaction
• FA is d ?
• t is board recoil time

5
FIG I.3 page 328
6
Conservation of L

• see Figure I.5 on page 330
• L stays constant while airborne
• ? changes due to changes in I
• k changes from layout to tuck, to layout

7
FIG I.5 page 330L I ?
8
FIG 15.1 page 494
9
Rotational Inertia I

• Resistance to a change in ? (angular accel.)
• I m x r²
• ? T ( Torque ? Rotational Inertia) I
  (Newtons 2nd Law, page 318)
• T I x ?

10
Turntable Demos L I ?

• Twists about Longitudinal Axis
• Spins about A-P Axis (break dance)
• Sommies about M-L Axis