# Homework Help: Roller Coaster Design Project HELP

1. Jan 2, 2008

### MissLlanas

Roller Coaster Design Project...HELP!!!

okay so here we go. I'll give everything I have haha. & if anyone can help me out at all it would be greatly appreciated. I'm very much LOST!
BTW! I'm not asking anyone to do the project for me, don't get the wrong idea. I did attempt it, I got a little more than half way through & I realized i was doing it incorrectly.
so I'd appreciate any help!! even if it's just on one problem :)

Objective:
Design a roller coaster and using the one meter of wire provided build a scale model of your roller coaster ride. Mount your coaster on something sturdy. Label at least 7 reference points.

Criteria
1. Coaster must be to scale (1:1000)
2. Fnormal on the rider must always be greater than or equal to zero.
3. Maxium acceleration on the rider = 6 g.
4. Design your coaster to include at least the following points;
(nvm that I'll skip it because I already have the design. It includes a first hill, a close to flat exit path, a second hill, and a loop..I also have that all measured to scale).
A picture illustrating the basic design I had in mind is attached.
the first hill being: 127 millimeter hence .127 meters
I'm not sure if I have to take measurement for the semi-flat exit path.
the second hill is 114.3 millimeters hence .114 meters
the loop 88.9 millimeters so .088 meters

Given
1. mass of coaster + passengers is 4500 Kg
2. Use gravitational field strength of 9.8 N/Kg

Calculation Questions:
1. Work done by the motor to bring the coaster to the top of the first hill
I realize W=Fd, however I'm used to being provided with at least two out of three of the values. I know my measured displacement is 127 m.m soo that's .127 meters...since I need to use meters. Hoowever I'm a little stuck on how to fidn the force? i initially attempted to use the given 4,500 Kg and multiply it by 60 m/s (because it is indirectly given in the criteria that acceleration must not exceed 6 g.) so upon solving it that way, I reached a solution of 34,290 J.

2. Total gravitational energy at the top of the first hill.
I know PEg = mgh, which would be 4,500 Kg) (9.8)(.127 m) = 5,600 J ????

3. Assume a 30 seconds for the car to reach the top of the first hill. Calculate the power expended by the motor.
P= W/t and so I would 34290 J/30 sec. = 1,143 W ???

4. Assume electricity costs \$0.07 per kilowatt-hour. If the motor and lift system is 25% efficient, how much will the electricity cost to run one ride?
completely stuck here!!

6. Determine the total mechanical energy left as the coaster arrives at each reference point. (Hint: this equals the total energy at the top of the first hill (A) minus the energy dissipated by the friction force during the section of the track between A and your reference point.)
7. At each reference point calculate PE, KE, and speed.
8. Determine the number of g's on the rider at each point, following these steps:
a. draw a force diagram showing the normal force (from seat), gravitational force and direction of acceleration.
b. write the equation for Newton's 2nd law to calculate Fnet on the coaster at each reference point.
c. solve for normal force at each point.
d. number of g's = normal force/force of gravity
9. Compare the normal force and g' s to the criteria listed at the beginning of the assignment. Make adjustments to your design if these don't meet criteria.
10. At three reference points of your choosing, calculate the momentum of the coaster.

if you can help me at all PLEASE do. even if it's only one problem I definitely need the help!

#### Attached Files:

• ###### coaster.JPG
File size:
11.5 KB
Views:
210
Last edited: Jan 2, 2008