Transcript Chapter 6 - Force and Motion II

Chapter 5 - Force and Motion II
• Friction
– Static
– Kinetic
• Incline/Horizontal Plane
with friction
• Drag Forces
– Terminal Velocity
• Uniform Circular Motion
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Banked and Flat Turns
Cresting Hills
Loop the Loops
Conical Pendulums
Ferris Wheels
Aircraft Turns
Friction
Ffr  k FN
Ffr  s FN
Coefficients of Friction
To push or pull a sled?
Or
Ffr  k FN
Measuring coefficients of friction
FN
Ffr
mg sin 
mg cos 

mg
s  tan 

k  tan 
Two boxes and a pulley
Incline plane (no friction)
• m2 = 7 kg
• Which way do
blocks move?
• What is
acceleration?
• What is tension
in cord?
Incline plane (friction)
s  0.40
k  0.30
• What range of
masses keep the
blocks at rest?
• If m2 = 10 kg,
determine the
system
acceleration
Uniform Circular Motion
2
v
aR 
r
v2
 FR  ma R  m r
Banked Roads
No friction required:
v  gr tan 
Conical Pendulum
v  gr tan   gLsin  tan 
T  2
L cos 
g
Motion in a vertical circle with gravity
• m = .150 kg
• r = 1.10 m
• Find minimum speed
to continue moving in
a circle
• If speed is twice this
minimum, find tension
in cord at top and
bottom.
Demo
Non-uniform circular motion
Velocity Dependent Forces
Terminal Velocity
dv
 Fy  bv  mg  m dt
b

t 

mg
m
v
1  e 
b 
