Linear Impulse Momentum Applications Chapter 9 KINE 3301
Biomechanics of Human Movement
Slide 2
The force shown below is applied to a 3 kg bowling ball with an
initial horizontal velocity of 2 m/s. Compute the final velocity of
the ball.
Slide 3
What was the impulse?
Slide 4
Integration of the force with respect to time (area under the
force time curve) can be used to obtain the velocity time
curve.
Slide 5
The two force curves shown below are applied to a 0.5 kg ball
with an initial horizontal velocity of 0 m/s. Compute the final
velocity of the ball after each force is applied. Draw an estimated
velocity-time curve that each force-time curve would produce.
Slide 6
Reaction Force Accelerates the CM The force applied accelerates
the ground in the direction of the force. The reaction force
accelerates the performers center of mass in the direction of the
reaction force.
Slide 7
Relationship between Force & Acceleration The shape of an
acceleration curve is the exactly the same as the force curve, only
the units are different.
Use the average force to compute braking impulse, propulsion
impulse and Vx at midstance (t =.112 s) and toe-off (t =.234
s).
Slide 11
Braking and Propulsion Braking < Propulsion Vx = +.46 m/s
Braking Propulsion Vx = +.01 m/s Braking > Propulsion Vx = .24
m/s
Slide 12
Free Body Diagram for Vertical Impulse - Momentum
Slide 13
Use the average force F Ave = 1007.075 N to compute the
vertical impulse and Vy at toe-off (t =.234 s).
Slide 14
Use the average force to compute braking impulse, propulsion
impulse and Vx at t = 0.04, t = 0.4, and t = 0.7 s. Walking
Forces
Slide 15
Use the average force F Ave = 621.88 N to compute the vertical
impulse and Vy at toe-off (t = 0.76 s).
Slide 16
Slide 17
Vertical Force & Acceleration for a Vertical Jump
Slide 18
Use the average force at each time point to compute the
vertical velocity. t = 0.2 s, F Ave = 440 N t = 0.4 s, F Ave = 632
N t = 0.6 s, F Ave = 904 N
Slide 19
Use the average force at each time point to compute the
vertical velocity. t = 0.2 s, F Ave = 440 N
Slide 20
Use the average force at each time point to compute the
vertical velocity. t = 0.4 s, F Ave = 632 N
Slide 21
Use the average force at each time point to compute the
vertical velocity. t = 0.6 s, F Ave = 904 N
Slide 22
At t = 0.4 sec the jumper has a vertical velocity (Vy i ) of
0.26 m/s. Use the average force from t =.4 to t =.6 to compute the
impulse and the final vertical velocity at t = 0.6 sec. t = 0.2 s,
F Ave = 1449 N