1. The Science of Welcome to Science of Stealth.
‘Big up’ National Science Week
Hide slides depending on age and ability of group.
There should be enough here to take to AS level.
Let’s start with basic principles – gravity
Next slide

2. Gravity (g) Gravity is a force of attraction between objects.
The more massive the object, the greater the pull. However, the object has to be really massive, like Earth, for the pull to be obvious.
Not afraid to poach from the NASA site.
Until recently, all roller coasters relied on gravity.
Use model and No Limits Roller coaster to demonstrate ( nominated pupil)
NASA at the Amusement Park

3. g forces High g’s Any acceleration greater than free fall.
> 9.8 m/s2
Low g’s
Any acceleration less than free fall.
< 1 g
< 9.8 m/s2
Earth’s gravity = 1 g
Provides a force of acceleration known as free fall (9.8 m/s2).
With rides – we show the accelerations in terms of g forces
No limits shows accelerations as part of the display.
Point out g forces
NASA at the Amusement Park

4. G forces In a theme park – you are likely to experience up to 5g
The safe limit is 7g for a healthy person for a short period.
Sustained levels of 10g will cause problems

5. Here are the basic facts for Stealth
Stealth Facts
Height metres
Launch time 2.3 seconds
Train weight 8 tonnes (unladen)
10 tonnes (laden)
Launch Speed 38 metres per second
Dive Speed 35 metres per second
Here are the basic facts for Stealth
I’ve used these figures, the profile diagram from the manufacturers and a Physics book to work out the following

6. Stealth acceleration Acceleration = v – u (m/s) t (s)
2.3
Acceleration = 16.5m/s2
16.5 = 1.68 x gravity
9.8
(v = final speed, u = initial speed, t = time)

7. I’ve looked at representing the data in three ways – take your pick.
Stealth v. Gravity
Time 1s 2s
2.3s
Gravity
9.8
19.6
22.5
Stealth
16.5
33.0
37.9
mps!
I’ve looked at representing the data in three ways – take your pick.

9. S = distance, u = initial velocity, a = acceleration, t = time
How far to reach 80mph?
S = ut + 1/2 at2
S = (0 x 2.3) + (16.5 x 2.3 x 2.3) 2
S =
S = 43.6m
S = distance, u = initial velocity, a = acceleration, t = time

10. Force to launch Stealth
Force = mass (kg) x acceleration (m/s2)
F = m x a
F = 10000kg x 16.5m/s2
F = kgm/s2
N (Newtons)
10 tonnes = 10000Kg

11. Work done in launching Stealth
Work = Force (N) x Distance (m)
Work = x 43.6
Work = Joules
Work = KJ
Work = 7.19 MJ

12. The Power of Stealth Power = work (J) time (s) Power = 7194000 2.3
Power = Watts
Power = 3.1MW

13. Potential energy needed= mgh As long as KE is greater than PE ………
Will you make it? –
Potential energy needed= mgh
PE = x 9.8 x 62
PE = J
Kinetic energy = I/2mv2
KE = I/2 x x 382
KE = J
As long as KE is greater than PE ………

14. ………Stealth will make it over the top

16. On the way up! Curve radius = 35m Centripetal force = mv2 r
Centripetal force = 100 x 38 x 38
on 100Kg rider
Centripetal force = 4125N
Force of 1g on a 100Kg person = 1000N
4125N = 4.1g
Total force on rider = 4.1g + 1.0g = 5.1g

17. On top of the world! PE = 6 480 000J KE = 7 220 000J
KE – PE = J
Surplus KE = J
KE = I/2mv2
v2 = 2KE = 2x = 148 m
v = 12+ m/s

18. Force of 1g on a 100Kg person = 1000N
On top of the world
Outside curve radius 8m
Centripetal force = mv2 r
Centripetal force = 100 x 12 x 12 8
Centripetal force = 1800N
Force of 1g on a 100Kg person = 1000N
Resultant force 800N = 0.8g
(almost weightless!)

19. On the way down! Curve radius 40m Centripetal force = mv2 r
Centripetal force = 100 x 35 x 35 40
Centripetal force = 3062N
Force of 1g on a 1000Kg person = 1000N
Resultant force on rider = 3.1g + 1.0g = 4.1g

21. Nitrogen accumulators

22. Hydraulic fluid

24. The motors - Medusa

25. Cylinder block

26. Winch drum

27. The catch car

28. Wire cable and return drum

29. Magnetic brakes Fail safe – no power required. Efficient
Maintenance free

30. Brakes! A metal plate moves through a permanent magnetic field.
Eddy currents in the field produce a force to oppose the motion.
The higher the speed – the greater the force.
Magnetic brakes never stop you completely. Air brakes finish the job

32. Brakes!

33. Brakes!

34. Keeping on track

36. Vortex Manufactured by KMG Europe/Chance Rides 2001 Height 20m
Max 120 degrees above vertical
4.5g max.
Ride capacity 32
500 per hour
Pendulum 9.2 rpm
Carousel 7.5 rpm
Duration 3 minutes

37. Pendulum

38. Vortex - Pendulum Length of arm 8.5m
Period T = 2π√l /g = 2x 3.14√8.5/9.8
= 5.82s
Frequency = 10.3 rpm
Actual = 9.2 rpm

39. Vortex - Pendulum Data: 9.2 rpm Length, l = 8m Displacement, x = 8m
Frequency of oscillation, f =9.2/60 = 0.15/s(Hz)
Acceleration, a = (2Πf)2x
= (6.28x1/6.5)2x8 = 7.46ms-2 (0.76g)

40. Motion in a circle

41. Vortex - Carousel Data: diameter, d= 8m, radius, r = 4m,
Frequency, f = 7.5/60 = /s (Hz)
Angular velocity ω = 2Πf
= 6.38 x = radians
Linear speed, v = ωr
= x 4 = 3.14m/s (7mph)

42. Vortex - Carousel Centripetal acceleration a = v2/r
= 3.142/4 = 2.46ms-2 (0.25g)

43. Salters Horners Jan 2008 A2 paper
6. On one type of theme park ride, a boat swings freely along a circular path from successively higher starting positions. As the boat moves through the lowest point on its swing, the riders are traveling at high speeds, and feel quite big forces on them.
With some rides, such as Rush at Thorpe Park, the highest starting point is with the supporting arm horizontal as shown.
Rush boat at starting point
18m
Boat
The length of the supporting arm of Rush is 18m. The mass of a typical rider is 70 kg.
(a) Calculate the maximum "g-force" felt by a typical rider on Rush.
“g-force" = force from seat
weight of rider

44. Questions?