engr 104: intro to engineering lab different strokes-golf analysis instructors: dr. binh q. tran dr....
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ENGR 104: Intro to Engineering Lab
Different Strokes-Golf Analysis
Instructors:Dr. Binh Q. Tran
Dr. Otto C. Wilson, Jr.
© 2002-09 The Catholic University of AmericaDept of Biomedical Engineering
EN
GR
104:
Int r
o t
o E
ng
i neer i
ng
Lab
Dept
of
Bio
medic
al En
gin
eeri
ng, C
at h
olic
Univ
ers
i ty
Lab Goals & Objective
The objective of this lab is to study the influence of friction on a moving body.
Students will design, develop, and perform lab experiments to compute frictional coefficients, f, on various surfaces.
EN
GR
104:
Int r
o t
o E
ng
i neer i
ng
Lab
Dept
of
Bio
medic
al En
gin
eeri
ng, C
at h
olic
Univ
ers
i ty
How can we model the friction problem?
Free-body diagram ???
EN
GR
104:
Int r
o t
o E
ng
i neer i
ng
Lab
Dept
of
Bio
medic
al En
gin
eeri
ng, C
at h
olic
Univ
ers
i ty
Free-Body Diagram
W=mg
Fx=max Ff=fW
Free Body DiagramPhysical System
EN
GR
104:
Int r
o t
o E
ng
i neer i
ng
Lab
Dept
of
Bio
medic
al En
gin
eeri
ng, C
at h
olic
Univ
ers
i ty
Kinematics Vector forms:
– Displacement: x = ix + jy
– Velocity: v = ivx + jvy
– Acceleration: a = iax + jvy
Recall from Projectile Motion Lecture:
vxf2 = vxo
2 + 2ax *(xf - xo)
If vxf = 0 (i.e. ball comes to stop),
0 = vxo2 + 2ax *(xf - xo)
xf = - vxo2 / 2ax (1)
EN
GR
104:
Int r
o t
o E
ng
i neer i
ng
Lab
Dept
of
Bio
medic
al En
gin
eeri
ng, C
at h
olic
Univ
ers
i ty
Newton’s Laws
Newton’s 3rd Law:Fx + Ff = 0 or Fx = - Ff
Fx = m * ax -Ff = -f* W
ax = -f *g (2)
thus, combine (1) & (2):xf = vxo
2 / 2gf
EN
GR
104:
Int r
o t
o E
ng
i neer i
ng
Lab
Dept
of
Bio
medic
al En
gin
eeri
ng, C
at h
olic
Univ
ers
i ty
Labview Interface
Develop Labview to compute velocity of the ball.– VI only gives times at leading & trailing edge of
pulse.– Need to write code to compute velocity & compute
friction coefficient
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