2. What we are covering today
• When is the contact force on a passenger
greatest on a rollercoaster
• How do you keep a passenger in their
seats while giving a white knuckle ride
3. The First Drop
Weight W
Support
force S
Centre of curvature
What is the support force you will feel
at the bottom of the slope?
Force up = S (reaction force)
Force down = mg (weight) + mv2
/r
If everyone stays in their seat the forces must balance
S = mg + mv2
/r
This is the extra force you feel!
http://www.nolimitscoaster.com/index.html
4. http://www.youtube.com/watch?v=h1VBSd_8Yys&feature=related
The Big Rush
Cable length (L)
Velocity (v)
Weight (mg)
Support force (s)
Start
position
All the potential energy at the
top of the swing is converted into
kinetic energy at the bottom.
Pe = Ke mgh = ½ mv2
V2
= 2gh
The support force
S = mg + mv2
/L
S = mg + 2mgh/L
The extra support force at the
bottom of the swinghttp://phet.colorado.edu/sims/pendulum-
lab/pendulum-lab_en.html
5. BIG WHEELSKeep on turnin’
The ride I used
to be too scared
to go on
A big wheel takes passengers on
the inside circumference, the wheel
must turn fast enough to stick the
passengers to the walls so they do
not fall out.
A big wheel takes passengers on
the inside circumference, the wheel
must turn fast enough to stick the
passengers to the walls so they do
not fall out.
At the maximum height the reaction
force (R) and the weight (mg) acts
downwards.
Reaction force (R)
The centrifugal force up must be greater
than the downwards force
mg + R = mv2
/rmg + R = mv2
/r
r
At the point the weight and centrifugal are
equal there will be no reaction force
At the point the weight and centrifugal are
equal there will be no reaction force
mg = mv2
/r
v2
= grv2
= grThe wheel has to go faster thanThe wheel has to go faster than
6. G - Force
• After around 4g passengers start blacking out!
• Rollercoaster designers have to make sure that there is never
an acceleration greater than (3g) 30 m/s2
http://puzzling.caret.cam.ac.uk/game.php?game=roller
http://www.youtube.com/watch?v=EXQKl-28zn0
7. G - Force
• After around 4g passengers start blacking out!
• Rollercoaster designers have to make sure that there is never
an acceleration greater than (3g) 30 m/s2
http://puzzling.caret.cam.ac.uk/game.php?game=roller
http://www.youtube.com/watch?v=EXQKl-28zn0
