I was delegated to investigate the physics aspects and principles involved with a theme park ride.

Khaled Hamid Page

Physics investigation

Introduction:

As part of a physics investigation, I was delegated to investigate the physics aspects and principles involved with a theme park ride. In the past it was usually roller coasters which were thoroughly examined, but I have chosen a ride that is a little far from the conventional; the ‘Tidal wave’, which is a giant log (wooden carriage) hurtling down from a high point down to a steep slope and in to water.

Upon investigating the roller coasters, the main aim was to identify two aspects of physics involved and to further discuss these principles/aspects in order to find the effect, its purpose and how it influences the ride itself and people on board it.

Identification of physics involved:

There are many aspects of physics involved in the ride but I am only set to discuss two. However, it would be relevant to mention how the other aspects of physics involved and how they affect each other.

The first aspect of physics which I noticed on the tidal was the acceleration and deceleration involved needed to bring the ride to a rest position. I also have chosen to discuss the force involved to ‘push’ the carriage down the steep slope.

Explanation of principle and its uses to the ‘Tidal wave’:

The acceleration is a measure of the rate at which the velocity of a particle is changing. On the ‘Tidal wave’, there is an acceleration as the carriage hurtles down into the water, but there is also a deceleration as the carriage goes into the water and comes to a stop. This deceleration is uniform and therefore can be calculated using the equations of motion i.e. s = ut + ½ at2. The non-uniform acceleration can be calculated using:

Acceleration = change in velocity/ time taken

The acceleration is used to create a thrilling experience for the rider. The acceleration has an effect which produces a weightlessness sensation on the rider, leaving the rider gasping for air for specific period. Where as the deceleration is used to slow down the ride and eventually bringing it to a rest, also a sigh of relief and wet clothes for those onboard.

Identification of physics involved:

The second aspect of physics I have chosen to discuss is the force involved.

Explanation of principle and its uses to the ‘Tidal wave’:

Newton’s second law stated that the equation a = F/m, which relates acceleration, force and mass. In particular, it shows that the bigger the force, the greater the acceleration it produces therefore the acceleration is proportional to the force: a – F

This relationship is the basis of Newton’s second law of motion:

The acceleration produced by a force when it ...

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Identification of physics involved:

The second aspect of physics I have chosen to discuss is the force involved.

Explanation of principle and its uses to the ‘Tidal wave’:

This relationship is the basis of Newton’s second law of motion:

The acceleration produced by a force when it acts on a body is proportional to the force and takes place in the direction of the force.

The equation also shows that the acceleration produced by a force depends on the mass of the object. The mass of an object is a measure of its inertia, or its ability to resist any change in its motion. The greater the mass, the smaller the acceleration which results, so the acceleration is inversely proportional to the mass:

A – 1/m

The force is not a component which is used directly to create any effects on the running of the ride. Therefore I can only discuss how much force is exerted by the object downhill and also the reaction force against it.

Diagram: Downward slope carriage

Water is about here

Account of one aspect (1):

I have chosen to discuss the acceleration in detail. On the tidal wave there is a positive acceleration and negative acceleration (deceleration). I have chosen to analyse the deceleration of the tidal wave, as this is not easily noticeable.

The force needed to generate the acceleration must be high, because of the high speed it travels at non-uniformly. Therefore the force needed to stop the ride must be relatively high to cause a deceleration. The acceleration which is negative as the carriage goes into the water is negative and can be calculated using a number of equations including:

* a = f/m – needs force to be calculated

*a= v – u / change in time (non –uniform acceleration)

The formulas can be used if the acceleration is non-uniform but for the tidal wave the deceleration is a constant so therefore the following formula is used:

S = ut + ½ at2

Account of one aspect (2): Where is the formula derived from and how is it related to ‘Tidal Wave’?

Think about the carriage moving along a straight line at the bottom of the hill with a constant acceleration (a). Suppose that its initial velocity, at a time is (u). After a further time (t), its velocity has increased to (v). From the definition of acceleration as (change in velocity)/(time taken) we have :

a = (v – u)/t, or re arranging to give v = u + at

From the definition of average velocity v = s/t we can find the distance by forming/rearranging to establish s = ut. The average velocity v is written in terms of the initial velocity u and final velocity v as:

V = u + v/2

And using the previous equations for v,

v = ( u + u + at )/2 = u + at/2

Substituting this we have:

S = ut + ½ at2

The right hand side of the equation is the sum of two terms. The ut term is the distance the carriage has travelled in time t; if it had been travelling with a constant speed u, and the ½ at2 terms is the additional distance travelled as a result of the acceleration

Diagram and analysis:

v = 0ms-1 s = 17m u = 14.13 ms-1 a = ? t = 3.47 sec

mass of carriage = 1500kg

number of people on carriage = 11

15 m

27 deg

The figures are not 100% correct. For the height I used Pythagoras theorem and the eyes were the tool for measurement so the calculations are relatively inaccurate due to human eye capabilities. I also had already calculated the initial velocity to be 14ms-1 from the point the carriage enters the water. After that, I had enough components to calculate the acceleration using the equation:

S = ut + ½ at2 (needs to be rearranged) to achieve:

a = s – ut/2t

by substituting the values the deceleration is calculated as :

a = 17m – (14.13 * 3 .37)

2 * 3.74 where a = -2.46 ms-1

The result showed there was a negative acceleration, (deceleration) just as I had assumed. The deceleration is due to the levelling of the steep hill at the bottom which reduces theta and therefore reduces speed. The air resistance and friction from wheels is negligible but the friction coming from the water is significant. The colliding water particles are in a liquid state, and act as a barrier trying to prevent the carriage from passing. This can be compared to the resistance in a wire, if it is long then the electrons have more particles obstructing it and therefore the wire is resisting. In this case, the water acts like ‘resistance’ and therefore tries to prevent the carriage from moving, resulting in a decrease in speed (deceleration) and eventually, this plus effect of gravity will take their effect and eventually put the carriage in ‘rest’ position.

Strengths and weaknesses:

There are some of using this type of height and steepness for such a ride. By making the ride steeper, the acceleration is increased due to air resistance and friction force being absent, the acceleration will equal:

a = g sin

Therefore the angle of the incline will increase, causing the acceleration to increase, too, and therefore causing the deceleration to increase, too, and therefore causing the deceleration to increase. This generates a more thrilling ride as it increases the sensation of weightlessness and the hormone adrenalin is released much faster increasing the deep breath during the ride.

Limitations:

There are some limitations to the ‘tidal wave’. As a ride it is functional according to the aims, however, the ‘tidal wave’, has a steep slope/angle and this needed to be carefully investigated. The steeper the slope, the more the acceleration increases, and too much of a slope could cause the carriage to travel down at uncontrollably fast speed, which could result in a derailment, so there is a safety aspect. The balance of generating a thrilling experience and being a safe ride needed to be considered deeply. The tidal wave looks like it has an acceptable slope which generates more then enough of a thrilling experience.

The second limitation is the volume of water used at the bottom of the slope. Currently, it creates enough of a force to decelerate the carriage, but it looks very uncomfortable for the rider. The large amount of water when in contact with the carriage as it comes down results in a quick ‘bang’ against the carriage. This shakes, the carriage and anyone inside it very much. Therefore this is another safety issue. The height of water and volume of water used should be proportional enough to generate a deceleration as the carriage comes down.

Future developments:

The ‘tidal wave’ is generally systematic at what it does and does not need a lot of key improvements, but merely safety checks and design questioning and researching.

However, the first improvement could be to let the carriage come down more from the slope before approaching or ‘crashing’ into the water. This results in less of a ‘bumpy’ ride for the riders and improves the safety issues of the carriage shaking too much and causing injuries.

The Tidal Wave as a ride is thrillingly satisfying and this is only due to the great height and acceleration. This is in turn provides the rider with a great feeling of weightlessness. However if the owners of the ride want to improve this, they should ensure that the Tidal Wave has more hills and slopes to make the ride more thrilling and worthwhile because at the moment the ride has one slope and the feeling of weightlessness is very short and at the end of the ride the rider expects to be very, very wet!

However I cannot suggest anymore improvements because the ride is a ‘log’ ride and only needs slopes and hills to generate a greater kinetic energy and increase acceleration.

One problem that could arise is a safety problem. The train has no seatbelts or a safety function to make sure the rider will stay put in the train, therefore I suggest that they add waist bands to the carriage to prevent young children with smaller mass from actually falling out. Although this has not happened, and the engineers have carefully calculated out the physic involved in preventing this, I think this would be a safer thing to do. It will also generate some psychological safety, juts like rollercoaster’s with shoulder pads.

Bibliography:

For this investigation I used my background knowledge as the main source of reference and information but the following books were also of aid: